Added type hints to the accounting application.

accounting/converters.py

@@ -142,14 +142,17 @@ class CashAccountConverter:
     """The path converter for the cash account."""
     regex = "0|(11|12|21|22)[1-9]{1,3}"
 
-    def to_python(self, value):
+    def to_python(self, value: str) -> Account:
         """Returns the cash account by the account code.
 
         Args:
-            value (str): The account code.
+            value: The account code.
 
         Returns:
-            Account: The account.
+            The account.
+
+        Raises:
+            ValueError: When the value is invalid
         """
         if value == "0":
             return Account(
@@ -164,14 +167,14 @@ class CashAccountConverter:
             raise ValueError
         return account
 
-    def to_url(self, value):
+    def to_url(self, value: Account) -> str:
         """Returns the code of an account.
 
         Args:
-            value (Account): The account.
+            value: The account.
 
         Returns:
-            str: The account code.
+            The account code.
         """
         return value.code
 
@@ -180,14 +183,17 @@ class LedgerAccountConverter:
     """The path converter for the ledger account."""
     regex = "[1-9]{1,5}"
 
-    def to_python(self, value):
+    def to_python(self, value: str) -> Account:
         """Returns the ledger account by the account code.
 
         Args:
-            value (str): The account code.
+            value: The account code.
 
         Returns:
-            Account: The account.
+            The account.
+
+        Raises:
+            ValueError: When the value is invalid
         """
         try:
             account = Account.objects.get(code=value)
@@ -197,14 +203,14 @@ class LedgerAccountConverter:
             raise ValueError
         return account
 
-    def to_url(self, value):
+    def to_url(self, value: Account) -> str:
         """Returns the code of an account.
 
         Args:
-            value (Account): The account.
+            value: The account.
 
         Returns:
-            str: The account code.
+            The account code.
         """
         return value.code
 
@@ -213,27 +219,30 @@ class TransactionConverter:
     """The path converter for the accounting transactions."""
     regex = "[1-9][0-9]{8}"
 
-    def to_python(self, value):
+    def to_python(self, value: str) -> Transaction:
         """Returns the transaction by the transaction ID.
 
         Args:
-            value (str): The transaction ID.
+            value: The transaction ID.
 
         Returns:
-            Transaction: The account.
+            The account.
+
+        Raises:
+            ValueError: When the value is invalid
         """
         try:
             return Transaction.objects.get(pk=value)
         except Transaction.DoesNotExist:
             raise ValueError
 
-    def to_url(self, value):
+    def to_url(self, value: Transaction) -> str:
         """Returns the ID of an account.
 
         Args:
-            value (Transaction): The transaction.
+            value: The transaction.
 
         Returns:
-            str: The transaction ID.
+            The transaction ID.
         """
         return value.pk

accounting/forms.py

@@ -19,6 +19,7 @@
 
 """
 import re
+from typing import Optional
 
 from django import forms
 from django.core.validators import RegexValidator
@@ -67,11 +68,11 @@ class RecordForm(forms.Form):
         self.txn_form = None
         self.is_credit = None
 
-    def account_title(self):
+    def account_title(self) -> Optional[str]:
         """Returns the title of the specified account, if any.
 
         Returns:
-            str: The title of the specified account, or None if the specified
+            The title of the specified account, or None if the specified
             account is not available.
         """
         try:
@@ -101,7 +102,7 @@ class RecordForm(forms.Form):
         if errors:
             raise forms.ValidationError(errors)
 
-    def _validate_transaction(self):
+    def _validate_transaction(self) -> None:
         """Validates whether the transaction matches the transaction form.
 
         Raises:
@@ -122,7 +123,7 @@ class RecordForm(forms.Form):
                         _("This record is not for this transaction."),
                         code="not_belong")
 
-    def _validate_account_type(self):
+    def _validate_account_type(self) -> None:
         """Validates whether the account is a correct debit or credit account.
 
         Raises:
@@ -145,7 +146,7 @@ class RecordForm(forms.Form):
                 self.add_error("account", error)
                 raise error
 
-    def _validate_is_credit(self):
+    def _validate_is_credit(self) -> None:
         """Validates whether debit and credit records are submitted correctly
         as corresponding debit and credit records.
 
@@ -250,7 +251,7 @@ class TransactionForm(forms.Form):
         if errors:
             raise forms.ValidationError(errors)
 
-    def _validate_has_debit_records(self):
+    def _validate_has_debit_records(self) -> None:
         """Validates whether there is any debit record.
 
         Raises:
@@ -268,7 +269,7 @@ class TransactionForm(forms.Form):
             _("Please fill in accounting records."),
             code="has_debit_records")
 
-    def _validate_has_credit_records(self):
+    def _validate_has_credit_records(self) -> None:
         """Validates whether there is any credit record.
 
         Raises:
@@ -286,7 +287,7 @@ class TransactionForm(forms.Form):
             _("Please fill in accounting records."),
             code="has_debit_records")
 
-    def _validate_balance(self):
+    def _validate_balance(self) -> None:
         """Validates whether the total amount of debit and credit records are
         consistent.
 
@@ -301,20 +302,20 @@ class TransactionForm(forms.Form):
             _("The total of the debit and credit amounts are inconsistent."),
             code="balance")
 
-    def is_valid(self):
+    def is_valid(self) -> bool:
-        if not super(TransactionForm, self).is_valid():
+        if not super().is_valid():
             return False
         for x in self.debit_records + self.credit_records:
             if not x.is_valid():
                 return False
         return True
 
-    def balance_error(self):
+    def balance_error(self) -> Optional[str]:
         """Returns the error message when the transaction is imbalanced.
 
         Returns:
-            str: The error message when the transaction is imbalanced, or
+            The error message when the transaction is imbalanced, or None
-                None otherwise.
+            otherwise.
         """
         errors = [x for x in self.non_field_errors().data
                   if x.code == "balance"]
@@ -322,20 +323,20 @@ class TransactionForm(forms.Form):
             return errors[0].message
         return None
 
-    def debit_total(self):
+    def debit_total(self) -> int:
         """Returns the total amount of the debit records.
 
         Returns:
-            int: The total amount of the credit records.
+            The total amount of the credit records.
         """
         return sum([int(x.data["amount"]) for x in self.debit_records
                     if "amount" in x.data and "amount" not in x.errors])
 
-    def credit_total(self):
+    def credit_total(self) -> int:
         """Returns the total amount of the credit records.
 
         Returns:
-            int: The total amount of the credit records.
+            The total amount of the credit records.
         """
         return sum([int(x.data["amount"]) for x in self.credit_records
                     if "amount" in x.data and "amount" not in x.errors])
@@ -366,7 +367,8 @@ class AccountForm(forms.Form):
         self.account = None
 
     @property
-    def parent(self):
+    def parent(self) -> Optional[Account]:
+        """The parent account, or None if this is the topmost account."""
         code = self["code"].value()
         if code is None or len(code) < 2:
             return None
@@ -391,7 +393,7 @@ class AccountForm(forms.Form):
         if errors:
             raise forms.ValidationError(errors)
 
-    def _validate_code_not_under_myself(self):
+    def _validate_code_not_under_myself(self) -> None:
         """Validates whether the code is under itself.
 
         Raises:
@@ -411,7 +413,7 @@ class AccountForm(forms.Form):
         self.add_error("code", error)
         raise error
 
-    def _validate_code_unique(self):
+    def _validate_code_unique(self) -> None:
         """Validates whether the code is unique.
 
         Raises:
@@ -432,7 +434,7 @@ class AccountForm(forms.Form):
         self.add_error("code", error)
         raise error
 
-    def _validate_code_parent_exists(self):
+    def _validate_code_parent_exists(self) -> None:
         """Validates whether the parent account exists.
 
         Raises:
@@ -452,7 +454,7 @@ class AccountForm(forms.Form):
             raise error
         return
 
-    def _validate_code_descendant_code_size(self):
+    def _validate_code_descendant_code_size(self) -> None:
         """Validates whether the codes of the descendants will be too long.
 
         Raises:
@@ -467,7 +469,7 @@ class AccountForm(forms.Form):
                     ~Q(pk=self.account.pk))\
             .aggregate(max_len=Max(Length("code")))["max_len"]
         if cur_max_len is None:
-            return True
+            return
         new_max_len = cur_max_len - len(self.account.code)\
             + len(self.data["code"])
         if new_max_len <= 5:

accounting/management/commands/accounting_sample.py

@@ -62,7 +62,7 @@ class Command(BaseCommand):
             user.save()
 
             p = Populator(user)
-            p.add_accounts((
+            p.add_accounts([
                 (1, "資產", "assets", "资产"),
                 (2, "負債", "liabilities", "负债"),
                 (3, "業主權益", "owners’ equity", "业主权益"),
@@ -124,7 +124,7 @@ class Command(BaseCommand):
                  "管理及总务费用"),
                 (6272, "伙食費", "meal (expenses)", "伙食费"),
                 (6273, "職工福利", "employee benefits/welfare", "职工福利"),
-            ))
+            ])
 
             income = random.randint(40000, 50000)
             pension = 882 if income <= 40100\
@@ -143,49 +143,49 @@ class Command(BaseCommand):
             month = (date.replace(day=1) - timezone.timedelta(days=1)).month
             p.add_transfer_transaction(
                 date,
-                ((1113, "薪資轉帳", savings),
+                [(1113, "薪資轉帳", savings),
                  (1314, F"勞保{month}月", pension),
                  (6262, F"健保{month}月", insurance),
-                 (1255, "代扣所得稅", tax)),
+                 (1255, "代扣所得稅", tax)],
-                ((4611, F"{month}月份薪水", income),))
+                [(4611, F"{month}月份薪水", income)])
 
             p.add_income_transaction(
                 -15,
-                ((1113, "ATM提款", 2000),))
+                [(1113, "ATM提款", 2000)])
             p.add_transfer_transaction(
                 -14,
-                ((6254, "高鐵—台北→左營", 1490),),
+                [(6254, "高鐵—台北→左營", 1490)],
-                ((2141, "高鐵—台北→左營", 1490),))
+                [(2141, "高鐵—台北→左營", 1490)])
             p.add_transfer_transaction(
                 -14,
-                ((6273, "電影—復仇者聯盟", 80),),
+                [(6273, "電影—復仇者聯盟", 80)],
-                ((2141, "電影—復仇者聯盟", 80),))
+                [(2141, "電影—復仇者聯盟", 80)])
             p.add_transfer_transaction(
                 -13,
-                ((6273, "電影—2001太空漫遊", 80),),
+                [(6273, "電影—2001太空漫遊", 80)],
-                ((2141, "電影—2001太空漫遊", 80),))
+                [(2141, "電影—2001太空漫遊", 80)])
             p.add_transfer_transaction(
                 -11,
-                ((2141, "電影—復仇者聯盟", 80),),
+                [(2141, "電影—復仇者聯盟", 80)],
-                ((1113, "電影—復仇者聯盟", 80),))
+                [(1113, "電影—復仇者聯盟", 80)])
 
             p.add_expense_transaction(
                 -13,
-                ((6273, "公車—262—民生社區→頂溪捷運站", 30),))
+                [(6273, "公車—262—民生社區→頂溪捷運站", 30)])
 
             p.add_expense_transaction(
                 -2,
-                ((6272, "午餐—排骨飯", random.randint(40, 200)),
+                [(6272, "午餐—排骨飯", random.randint(40, 200)),
-                 (6272, "飲料—紅茶", random.randint(40, 200))))
+                 (6272, "飲料—紅茶", random.randint(40, 200))])
             p.add_expense_transaction(
                 -1,
-                ((6272, "午餐—牛肉麵", random.randint(40, 200)),
+                ([(6272, "午餐—牛肉麵", random.randint(40, 200)),
-                 (6272, "飲料—紅茶", random.randint(40, 200))))
+                 (6272, "飲料—紅茶", random.randint(40, 200))]))
             p.add_expense_transaction(
                 -1,
-                ((6272, "午餐—排骨飯", random.randint(40, 200)),
+                [(6272, "午餐—排骨飯", random.randint(40, 200)),
-                 (6272, "飲料—冬瓜茶", random.randint(40, 200))))
+                 (6272, "飲料—冬瓜茶", random.randint(40, 200))])
             p.add_expense_transaction(
                 0,
-                ((6272, "午餐—雞腿飯", random.randint(40, 200)),
+                [(6272, "午餐—雞腿飯", random.randint(40, 200)),
-                 (6272, "飲料—咖啡", random.randint(40, 200))))
+                 (6272, "飲料—咖啡", random.randint(40, 200))])

accounting/models.py

@@ -18,6 +18,9 @@
 """The data models of the accounting application.
 
 """
+import datetime
+from typing import Dict, List, Optional
+
 from dirtyfields import DirtyFieldsMixin
 from django.conf import settings
 from django.db import models, transaction
@@ -83,51 +86,44 @@ class Account(DirtyFieldsMixin, models.Model):
         db_table = "accounting_accounts"
 
     @property
-    def title(self):
+    def title(self) -> str:
+        """The title in the current language."""
         return get_multi_lingual_attr(self, "title")
 
     @title.setter
-    def title(self, value):
+    def title(self, value: str) -> None:
         set_multi_lingual_attr(self, "title", value)
 
     @property
-    def option_data(self):
+    def option_data(self) -> Dict[str, str]:
+        """The data as an option."""
         return {
             "code": self.code,
             "title": self.title,
         }
 
     @property
-    def is_parent_and_in_use(self):
+    def is_parent_and_in_use(self) -> bool:
-        """Whether this is a parent account and is in use.
+        """Whether this is a parent account and is in use."""
-
-        Returns:
-            bool: True if this is a parent account and is in use, or false
-                otherwise
-        """
         if self._is_parent_and_in_use is None:
             self._is_parent_and_in_use = self.child_set.count() > 0\
                                          and self.record_set.count() > 0
         return self._is_parent_and_in_use
 
     @is_parent_and_in_use.setter
-    def is_parent_and_in_use(self, value):
+    def is_parent_and_in_use(self, value: bool) -> None:
         self._is_parent_and_in_use = value
 
     @property
-    def is_in_use(self):
+    def is_in_use(self) -> bool:
-        """Whether this account is in use.
+        """Whether this account is in use."""
-
-        Returns:
-            bool: True if this account is in use, or false otherwise.
-        """
         if self._is_in_use is None:
             self._is_in_use = self.child_set.count() > 0\
                               or self.record_set.count() > 0
         return self._is_in_use
 
     @is_in_use.setter
-    def is_in_use(self, value):
+    def is_in_use(self, value: bool) -> None:
         self._is_in_use = value
 
 
@@ -157,7 +153,7 @@ class Transaction(DirtyFieldsMixin, models.Model):
         transaction."""
         return self.date.__str__() + " #" + self.ord.__str__()
 
-    def get_absolute_url(self):
+    def get_absolute_url(self) -> str:
         """Returns the URL to view this transaction."""
         if self.is_cash_expense:
             return reverse(
@@ -169,13 +165,13 @@ class Transaction(DirtyFieldsMixin, models.Model):
             return reverse(
                 "accounting:transactions.detail", args=("transfer", self))
 
-    def is_dirty(self, check_relationship=False, check_m2m=None):
+    def is_dirty(self, check_relationship=False, check_m2m=None) -> bool:
         """Returns whether the data of this transaction is changed and need
         to be saved into the database.
 
         Returns:
-            bool: True if the data of this transaction is changed and need
+            True if the data of this transaction is changed and need to be
-                to be saved into the database, or False otherwise.
+            saved into the database, or False otherwise.
         """
         if super().is_dirty(check_relationship=check_relationship,
                             check_m2m=check_m2m):
@@ -189,8 +185,9 @@ class Transaction(DirtyFieldsMixin, models.Model):
             return True
         return False
 
-    def save(self, current_user=None, old_date=None, force_insert=False,
+    def save(self, current_user=None, old_date: datetime.date = None,
-             force_update=False, using=None, update_fields=None):
+             force_insert=False, force_update=False, using=None,
+             update_fields=None):
         # When the date is changed, the orders of the transactions in the same
         # day need to be reordered
         txn_to_sort = []
@@ -262,7 +259,7 @@ class Transaction(DirtyFieldsMixin, models.Model):
         """The records of the transaction.
 
         Returns:
-            list[Record]: The records.
+            List[Record]: The records.
         """
         if self._records is None:
             self._records = list(self.record_set.all())
@@ -278,22 +275,18 @@ class Transaction(DirtyFieldsMixin, models.Model):
         """The debit records of this transaction.
 
         Returns:
-            list[Record]: The records.
+            List[Record]: The records.
         """
         return [x for x in self.records if not x.is_credit]
 
-    def debit_total(self):
+    def debit_total(self) -> int:
         """The total amount of the debit records."""
         return sum([x.amount for x in self.debit_records
                     if isinstance(x.amount, int)])
 
     @property
-    def debit_summaries(self):
+    def debit_summaries(self) -> List[str]:
-        """The summaries of the debit records.
+        """The summaries of the debit records."""
-
-        Returns:
-            list[str]: The summaries of the debit records.
-        """
         return [x.account.title if x.summary is None else x.summary
                 for x in self.debit_records]
 
@@ -302,36 +295,28 @@ class Transaction(DirtyFieldsMixin, models.Model):
         """The credit records of this transaction.
 
         Returns:
-            list[Record]: The records.
+            List[Record]: The records.
         """
         return [x for x in self.records if x.is_credit]
 
-    def credit_total(self):
+    def credit_total(self) -> int:
         """The total amount of the credit records."""
         return sum([x.amount for x in self.credit_records
                     if isinstance(x.amount, int)])
 
     @property
-    def credit_summaries(self):
+    def credit_summaries(self) -> List[str]:
-        """The summaries of the credit records.
+        """The summaries of the credit records."""
-
-        Returns:
-            list[str]: The summaries of the credit records.
-        """
         return [x.account.title if x.summary is None else x.summary
                 for x in self.credit_records]
 
     @property
-    def amount(self):
+    def amount(self) -> int:
-        """The amount of this transaction.
+        """The amount of this transaction."""
-
-        Returns:
-            int: The amount of this transaction.
-        """
         return self.debit_total()
 
     @property
-    def is_balanced(self):
+    def is_balanced(self) -> bool:
         """Whether the sum of the amounts of the debit records is the
         same as the sum of the amounts of the credit records. """
         if self._is_balanced is None:
@@ -341,16 +326,16 @@ class Transaction(DirtyFieldsMixin, models.Model):
         return self._is_balanced
 
     @is_balanced.setter
-    def is_balanced(self, value):
+    def is_balanced(self, value: bool) -> None:
         self._is_balanced = value
 
-    def has_many_same_day(self):
+    def has_many_same_day(self) -> bool:
         """whether there are more than one transactions at this day,
         so that the user can sort their orders. """
         return Transaction.objects.filter(date=self.date).count() > 1
 
     @property
-    def has_order_hole(self):
+    def has_order_hole(self) -> bool:
         """Whether the order of the transactions on this day is not
         1, 2, 3, 4, 5..., and should be reordered. """
         if self._has_order_hole is None:
@@ -369,11 +354,11 @@ class Transaction(DirtyFieldsMixin, models.Model):
         return self._has_order_hole
 
     @has_order_hole.setter
-    def has_order_hole(self, value):
+    def has_order_hole(self, value: bool) -> None:
         self._has_order_hole = value
 
     @property
-    def is_cash_income(self):
+    def is_cash_income(self) -> bool:
         """Whether this transaction is a cash income transaction."""
         debit_records = self.debit_records
         return (len(debit_records) == 1
@@ -381,7 +366,7 @@ class Transaction(DirtyFieldsMixin, models.Model):
                 and debit_records[0].summary is None)
 
     @property
-    def is_cash_expense(self):
+    def is_cash_expense(self) -> bool:
         """Whether this transaction is a cash expense transaction."""
         credit_records = self.credit_records
         return (len(credit_records) == 1
@@ -389,7 +374,7 @@ class Transaction(DirtyFieldsMixin, models.Model):
                 and credit_records[0].summary is None)
 
     @property
-    def type(self):
+    def type(self) -> str:
         """The transaction type."""
         if self.is_cash_expense:
             return "expense"
@@ -444,40 +429,40 @@ class Record(DirtyFieldsMixin, models.Model):
         db_table = "accounting_records"
 
     @property
-    def debit_amount(self):
+    def debit_amount(self) -> Optional[int]:
         """The debit amount of this accounting record."""
         if self._debit_amount is None:
             self._debit_amount = self.amount if not self.is_credit else None
         return self._debit_amount
 
     @debit_amount.setter
-    def debit_amount(self, value):
+    def debit_amount(self, value: Optional[int]) -> None:
         self._debit_amount = value
 
     @property
-    def credit_amount(self):
+    def credit_amount(self) -> Optional[int]:
         """The credit amount of this accounting record."""
         if self._credit_amount is None:
             self._credit_amount = self.amount if self.is_credit else None
         return self._credit_amount
 
     @credit_amount.setter
-    def credit_amount(self, value):
+    def credit_amount(self, value: Optional[int]):
         self._credit_amount = value
 
     @property
-    def is_balanced(self):
+    def is_balanced(self) -> bool:
         """Whether the transaction of this record is balanced. """
         if self._is_balanced is None:
             self._is_balanced = self.transaction.is_balanced
         return self._is_balanced
 
     @is_balanced.setter
-    def is_balanced(self, value):
+    def is_balanced(self, value: bool) -> None:
         self._is_balanced = value
 
     @property
-    def has_order_hole(self):
+    def has_order_hole(self) -> bool:
         """Whether the order of the transactions on this day is not
         1, 2, 3, 4, 5..., and should be reordered. """
         if self._has_order_hole is None:
@@ -485,5 +470,5 @@ class Record(DirtyFieldsMixin, models.Model):
         return self._has_order_hole
 
     @has_order_hole.setter
-    def has_order_hole(self, value):
+    def has_order_hole(self, value: bool) -> None:
         self._has_order_hole = value

accounting/templatetags/accounting.py

@@ -19,6 +19,7 @@
 
 """
 import re
+from typing import Union, Optional
 
 from django import template
 
@@ -30,7 +31,7 @@ register = template.Library()
 
 
 @register.filter
-def accounting_amount(value):
+def accounting_amount(value: Union[str, int]) -> str:
     if value is None:
         return ""
     if value == 0:
@@ -47,13 +48,15 @@ def accounting_amount(value):
 
 
 @register.simple_tag
-def report_url(cash_account, ledger_account, period):
+def report_url(cash_account: Optional[Account],
+               ledger_account: Optional[Account],
+               period: Optional[Period]) -> ReportUrl:
     """Returns accounting report URL helper.
 
     Args:
-        cash_account (Account): The current cash account.
+        cash_account: The current cash account.
-        ledger_account (Account): The current ledger account.
+        ledger_account: The current ledger account.
-        period (Period): The period.
+        period: The period.
 
     Returns:
         ReportUrl: The accounting report URL helper.

accounting/utils.py

@@ -21,6 +21,7 @@
 import datetime
 import json
 import re
+from typing import Union, Tuple, List, Optional, Iterable, Mapping, Dict
 
 from django.conf import settings
 from django.core.exceptions import ObjectDoesNotExist
@@ -37,6 +38,9 @@ from mia_core.utils import new_pk
 from .forms import TransactionForm, RecordForm
 from .models import Account, Transaction, Record
 
+AccountData = Tuple[Union[str, int], str, str, str]
+RecordData = Tuple[Union[str, int], Optional[str], int]
+
 DEFAULT_CASH_ACCOUNT = "1111"
 CASH_SHORTCUT_ACCOUNTS = ["0", "1111"]
 DEFAULT_LEDGER_ACCOUNT = "1111"
@@ -48,12 +52,12 @@ class MonthlySummary:
     """A summary record.
 
     Args:
-        month (datetime.date): The month.
+        month: The month.
-        label (str): The text label.
+        label: The text label.
-        credit (int): The credit amount.
+        credit: The credit amount.
-        debit (int): The debit amount.
+        debit: The debit amount.
-        balance (int): The balance.
+        balance: The balance.
-        cumulative_balance (int): The cumulative balance.
+        cumulative_balance: The cumulative balance.
 
     Attributes:
         month (datetime.date): The month.
@@ -64,8 +68,9 @@ class MonthlySummary:
         cumulative_balance (int): The cumulative balance.
     """
 
-    def __init__(self, month=None, label=None, credit=None, debit=None,
+    def __init__(self, month: datetime.date = None, label: str = None,
-                 balance=None, cumulative_balance=None):
+                 credit: int = None, debit: int = None, balance: int = None,
+                 cumulative_balance: int = None):
         self.month = month
         self.label = label
         self.credit = credit
@@ -80,43 +85,42 @@ class ReportUrl:
     """The URL of the accounting reports.
 
     Args:
-        cash (Account): The currently-specified account of the
+        cash: The currently-specified account of the
             cash account or cash summary.
-        ledger (Account): The currently-specified account of the
+        ledger: The currently-specified account of the
             ledger or leger summary.
-        period (Period): The currently-specified period.
+        period: The currently-specified period.
     """
 
-    def __init__(self, cash=None, ledger=None, period=None):
+    def __init__(self, cash: Account = None, ledger: Account = None,
+                 period: Period = None):
         self._period = Period() if period is None else period
         self._cash = get_default_cash_account() if cash is None else cash
         self._ledger = get_default_ledger_account()\
             if ledger is None else ledger
 
-    def cash(self):
+    def cash(self) -> str:
-        return reverse(
+        return reverse("accounting:cash", args=(self._cash, self._period))
-            "accounting:cash", args=(self._cash, self._period))
 
-    def cash_summary(self):
+    def cash_summary(self) -> str:
         return reverse("accounting:cash-summary", args=(self._cash,))
 
-    def ledger(self):
+    def ledger(self) -> str:
-        return reverse(
+        return reverse("accounting:ledger", args=(self._ledger, self._period))
-            "accounting:ledger", args=(self._ledger, self._period))
 
-    def ledger_summary(self):
+    def ledger_summary(self) -> str:
         return reverse("accounting:ledger-summary", args=(self._ledger,))
 
-    def journal(self):
+    def journal(self) -> str:
         return reverse("accounting:journal", args=(self._period,))
 
-    def trial_balance(self):
+    def trial_balance(self) -> str:
         return reverse("accounting:trial-balance", args=(self._period,))
 
-    def income_statement(self):
+    def income_statement(self) -> str:
         return reverse("accounting:income-statement", args=(self._period,))
 
-    def balance_sheet(self):
+    def balance_sheet(self) -> str:
         return reverse("accounting:balance-sheet", args=(self._period,))
 
 
@@ -124,7 +128,7 @@ class Populator:
     """The helper to populate the accounting data.
 
     Args:
-        user (User): The user in action.
+        user: The user in action.
 
     Attributes:
         user (User): The user in action.
@@ -133,7 +137,7 @@ class Populator:
     def __init__(self, user):
         self.user = user
 
-    def add_accounts(self, accounts):
+    def add_accounts(self, accounts: List[AccountData]) -> None:
         """Adds accounts.
 
         Args:
@@ -152,16 +156,16 @@ class Populator:
                     title_zh_hans=data[3],
                     created_by=self.user, updated_by=self.user).save()
 
-    def add_transfer_transaction(self, date, debit, credit):
+    def add_transfer_transaction(self, date: Union[datetime.date, int],
+                                 debit: List[RecordData],
+                                 credit: List[RecordData]) -> None:
         """Adds a transfer transaction.
 
         Args:
-            date (datetime.date|int): The date, or the number of days from
+            date: The date, or the number of days from
                 today.
-            debit (tuple[tuple[any]]): Tuples of (account, summary, amount)
+            debit: Tuples of (account, summary, amount) of the debit records.
-                of the debit records.
+            credit: Tuples of (account, summary, amount) of the credit records.
-            credit (tuple[tuple[any]]): Tuples of (account, summary, amount)
-                of the credit records.
         """
         if isinstance(date, int):
             date = timezone.localdate() + timezone.timedelta(days=date)
@@ -196,38 +200,36 @@ class Populator:
                                           updated_by=self.user)
             order = order + 1
 
-    def add_income_transaction(self, date, credit):
+    def add_income_transaction(self, date: Union[datetime.date, int],
+                               credit: List[RecordData]) -> None:
         """Adds a cash income transaction.
 
         Args:
-            date (datetime.date|int): The date, or the number of days from
+            date: The date, or the number of days from today.
-                today.
+            credit: Tuples of (account, summary, amount) of the credit records.
-            credit (tuple[tuple[any]]): Tuples of (account, summary, amount) of
-                the credit records.
         """
         amount = sum([x[2] for x in credit])
         self.add_transfer_transaction(
-            date, ((Account.CASH, None, amount),), credit)
+            date, [(Account.CASH, None, amount)], credit)
 
-    def add_expense_transaction(self, date, debit):
+    def add_expense_transaction(self, date: Union[datetime.date, int],
+                                debit: List[RecordData]) -> None:
         """Adds a cash income transaction.
 
         Args:
-            date (datetime.date|int): The date, or the number of days from
+            date: The date, or the number of days from today.
-                today.
+            debit: Tuples of (account, summary, amount) of the debit records.
-            debit (tuple[tuple[any]]): Tuples of (account, summary, amount) of
-                the debit records.
         """
         amount = sum([x[2] for x in debit])
         self.add_transfer_transaction(
-            date, debit, ((Account.CASH, None, amount),))
+            date, debit, [(Account.CASH, None, amount)])
 
 
-def get_cash_accounts():
+def get_cash_accounts() -> List[Account]:
     """Returns the cash accounts.
 
     Returns:
-        list[Account]: The cash accounts.
+        The cash accounts.
     """
     accounts = list(
         Account.objects
@@ -247,11 +249,11 @@ def get_cash_accounts():
     return accounts
 
 
-def get_default_cash_account():
+def get_default_cash_account() -> Account:
     """Returns the default cash account.
 
     Returns:
-        Account: The default cash account.
+        The default cash account.
     """
     try:
         code = settings.ACCOUNTING["DEFAULT_CASH_ACCOUNT"]
@@ -274,11 +276,11 @@ def get_default_cash_account():
     return Account(code="0", title=_("current assets and liabilities"))
 
 
-def get_cash_shortcut_accounts():
+def get_cash_shortcut_accounts() -> List[str]:
     """Returns the codes of the shortcut cash accounts.
 
     Returns:
-        list[str]: The codes of the shortcut cash accounts.
+        The codes of the shortcut cash accounts.
     """
     try:
         accounts = settings.ACCOUNTING["CASH_SHORTCUT_ACCOUNTS"]
@@ -293,11 +295,11 @@ def get_cash_shortcut_accounts():
     return accounts
 
 
-def get_ledger_accounts():
+def get_ledger_accounts() -> List[Account]:
     """Returns the accounts for the ledger.
 
     Returns:
-        list[Account]: The accounts for the ledger.
+        The accounts for the ledger.
     """
     """
     For SQL one-liner:
@@ -315,18 +317,19 @@ SELECT s.*
     """
     codes = {}
     for code in [x.code for x in Account.objects
-            .annotate(Count("record")).filter(record__count__gt=0)]:
+                 .annotate(Count("record"))
+                 .filter(record__count__gt=0)]:
         while len(code) > 0:
             codes[code] = True
             code = code[:-1]
     return Account.objects.filter(code__in=codes).order_by("code")
 
 
-def get_default_ledger_account():
+def get_default_ledger_account() -> Optional[Account]:
     """Returns the default ledger account.
 
     Returns:
-        Account: The default ledger account.
+        The default ledger account.
     """
     try:
         code = settings.ACCOUNTING["DEFAULT_CASH_ACCOUNT"]
@@ -347,12 +350,12 @@ def get_default_ledger_account():
     return None
 
 
-def find_imbalanced(records):
+def find_imbalanced(records: Iterable[Record]) -> None:
     """"Finds the records with imbalanced transactions, and sets their
     is_balanced attribute.
 
     Args:
-        records (list[Record]): The accounting records.
+        records: The accounting records.
     """
     imbalanced = [x.pk for x in Transaction.objects
                   .annotate(
@@ -364,13 +367,13 @@ def find_imbalanced(records):
         record.is_balanced = record.transaction.pk not in imbalanced
 
 
-def find_order_holes(records):
+def find_order_holes(records: Iterable[Record]) -> None:
     """"Finds whether the order of the transactions on this day is not
         1, 2, 3, 4, 5..., and should be reordered, and sets their
         has_order_holes attributes.
 
     Args:
-        records (list[Record]): The accounting records.
+        records: The accounting records.
     """
     holes = [x["date"] for x in Transaction.objects
              .values("date")
@@ -387,12 +390,12 @@ def find_order_holes(records):
                                 and record.transaction.date in holes
 
 
-def find_payable_records(account, records):
+def find_payable_records(account: Account, records: Iterable[Record]) -> None:
     """Finds and sets the whether the payable record is paid.
 
     Args:
-        account (Account): The current ledger account.
+        account: The current ledger account.
-        records (list[Record]): The accounting records.
+        records: The accounting records.
     """
     try:
         payable_accounts = settings.ACCOUNTING["PAYABLE_ACCOUNTS"]
@@ -422,12 +425,13 @@ def find_payable_records(account, records):
         x.is_payable = True
 
 
-def find_existing_equipments(account, records):
+def find_existing_equipments(account: Account,
+                             records: Iterable[Record]) -> None:
     """Finds and sets the equipments that still exist.
 
     Args:
-        account (Account): The current ledger account.
+        account: The current ledger account.
-        records (list[Record]): The accounting records.
+        records: The accounting records.
     """
     try:
         equipment_accounts = settings.ACCOUNTING["EQUIPMENT_ACCOUNTS"]
@@ -457,13 +461,13 @@ def find_existing_equipments(account, records):
         x.is_existing_equipment = True
 
 
-def get_summary_categories():
+def get_summary_categories() -> str:
     """Finds and returns the summary categories and their corresponding account
-    hints.
+    hints as JSON.
 
     Returns:
-        dict[str,str]: The summary categories and their account hints, by
+        The summary categories and their account hints, by their record types
-            their record types and category types.
+        and category types.
     """
     rows = Record.objects\
         .filter(Q(summary__contains="—"),
@@ -507,14 +511,15 @@ def get_summary_categories():
     return json.dumps(categories)
 
 
-def fill_txn_from_post(txn_type, txn, post):
+def fill_txn_from_post(txn_type: str, txn: Transaction,
+                       post: Mapping[str, str]) -> None:
     """Fills the transaction from the POSTed data.  The POSTed data must be
     validated and clean at this moment.
 
     Args:
-        txn_type (str): The transaction type.
+        txn_type: The transaction type.
-        txn (Transaction): The transaction.
+        txn: The transaction.
-        post (dict): The POSTed data.
+        post: The POSTed data.
     """
     m = re.match("^([0-9]{4})-([0-9]{2})-([0-9]{2})$", post["date"])
     txn.date = datetime.date(
@@ -565,12 +570,12 @@ def fill_txn_from_post(txn_type, txn, post):
     txn.records = records
 
 
-def sort_post_txn_records(post):
+def sort_post_txn_records(post: Dict[str, str]) -> None:
     """Sorts the records in the form by their specified order, so that the
     form can be used to populate the data to return to the user.
 
     Args:
-        post (dict): The POSTed form.
+        post: The POSTed form.
     """
     # Collects the available record numbers
     record_no = {
@@ -618,15 +623,16 @@ def sort_post_txn_records(post):
         post[key] = new_post[key]
 
 
-def make_txn_form_from_model(txn_type, txn):
+def make_txn_form_from_model(txn_type: str,
+                             txn: Transaction) -> TransactionForm:
     """Converts a transaction data model to a transaction form.
 
     Args:
-        txn_type (str): The transaction type.
+        txn_type: The transaction type.
-        txn (Transaction): The transaction data model.
+        txn: The transaction data model.
 
     Returns:
-        TransactionForm: The transaction form.
+        The transaction form.
     """
     form = TransactionForm(
         {x: str(getattr(txn, x)) for x in ["date", "notes"]
@@ -658,7 +664,8 @@ def make_txn_form_from_model(txn_type, txn):
     return form
 
 
-def _find_max_record_no(txn_type, post):
+def _find_max_record_no(txn_type: str,
+                        post: Mapping[str, str]) -> Dict[str, int]:
     """Finds the max debit and record numbers from the POSTed form.
 
     Args:

accounting/validators.py

@@ -25,11 +25,11 @@ from django.utils.translation import gettext as _
 from .models import Account, Record
 
 
-def validate_record_id(value):
+def validate_record_id(value: str) -> None:
     """Validates the record ID.
 
     Args:
-        value (str): The record ID.
+        value: The record ID.
 
     Raises:
         ValidationError: When the validation fails.
@@ -41,11 +41,11 @@ def validate_record_id(value):
                               code="not_exist")
 
 
-def validate_record_account_code(value):
+def validate_record_account_code(value: str) -> None:
     """Validates an account code.
 
     Args:
-        value (str): The account code.
+        value: The account code.
 
     Raises:
         ValidationError: When the validation fails.

accounting/views.py

@@ -18,6 +18,7 @@
 """The view controllers of the accounting application.
 
 """
+import datetime
 import json
 import re
 
@@ -26,7 +27,8 @@ from django.db import transaction
 from django.db.models import Sum, Case, When, F, Q, Count, BooleanField, \
     ExpressionWrapper
 from django.db.models.functions import TruncMonth, Coalesce
-from django.http import JsonResponse, HttpResponseRedirect, Http404
+from django.http import JsonResponse, HttpResponseRedirect, Http404, \
+    HttpRequest, HttpResponse
 from django.shortcuts import render, redirect
 from django.template.loader import render_to_string
 from django.urls import reverse
@@ -62,16 +64,17 @@ class CashDefaultView(RedirectView):
 
 @require_GET
 @login_required
-def cash(request, account, period):
+def cash(request: HttpRequest, account: Account,
+         period: Period) -> HttpResponse:
     """The cash account.
 
     Args:
-        request (HttpRequest) The request.
+        request: The request.
-        account (Account): The account.
+        account: The account.
-        period (Period): The period.
+        period: The period.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     # The accounting records
     if account.code == "0":
@@ -180,15 +183,15 @@ class CashSummaryDefaultView(RedirectView):
 
 @require_GET
 @login_required
-def cash_summary(request, account):
+def cash_summary(request: HttpRequest, account: Account) -> HttpResponse:
     """The cash account summary.
 
     Args:
-        request (HttpRequest) The request.
+        request: The request.
-        account (Account): The account.
+        account: The account.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     # The account
     accounts = utils.get_cash_accounts()
@@ -278,16 +281,17 @@ class LedgerDefaultView(RedirectView):
 
 @require_GET
 @login_required
-def ledger(request, account, period):
+def ledger(request: HttpRequest, account: Account,
+           period: Period) -> HttpResponse:
     """The ledger.
 
     Args:
-        request (HttpRequest) The request.
+        request: The request.
-        account (Account): The account.
+        account: The account.
-        period (Period): The period.
+        period: The period.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     # The accounting records
     records = list(
@@ -354,15 +358,15 @@ class LedgerSummaryDefaultView(RedirectView):
 
 @require_GET
 @login_required
-def ledger_summary(request, account):
+def ledger_summary(request: HttpRequest, account: Account) -> HttpResponse:
     """The ledger summary report.
 
     Args:
-        request (HttpRequest) The request.
+        request: The request.
-        account (Account): The account.
+        account: The account.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     # The month summaries
     months = [utils.MonthlySummary(**x) for x in Record.objects
@@ -416,15 +420,15 @@ class JournalDefaultView(RedirectView):
 
 @require_GET
 @login_required
-def journal(request, period):
+def journal(request: HttpRequest, period: Period) -> HttpResponse:
     """The journal.
 
     Args:
-        request (HttpRequest) The request.
+        request: The request.
-        period (Period): The period.
+        period: The period.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     # The accounting records
     records = Record.objects \
@@ -498,15 +502,15 @@ class TrialBalanceDefaultView(RedirectView):
 
 @require_GET
 @login_required
-def trial_balance(request, period):
+def trial_balance(request: HttpRequest, period: Period) -> HttpResponse:
     """The trial balance.
 
     Args:
-        request (HttpRequest) The request.
+        request: The request.
-        period (Period): The period.
+        period: The period.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     # The accounts
     nominal = list(
@@ -601,15 +605,15 @@ class IncomeStatementDefaultView(RedirectView):
 
 @require_GET
 @login_required
-def income_statement(request, period):
+def income_statement(request: HttpRequest, period: Period) -> HttpResponse:
     """The income statement.
 
     Args:
-        request (HttpRequest) The request.
+        request: The request.
-        period (Period): The period.
+        period: The period.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     # The accounts
     accounts = list(
@@ -676,15 +680,15 @@ class BalanceSheetDefaultView(RedirectView):
 
 @require_GET
 @login_required
-def balance_sheet(request, period):
+def balance_sheet(request: HttpRequest, period: Period) -> HttpResponse:
     """The balance sheet.
 
     Args:
-        request (HttpRequest) The request.
+        request: The request.
-        period (Period): The period.
+        period: The period.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     # The accounts
     accounts = list(
@@ -764,14 +768,14 @@ def balance_sheet(request, period):
 
 @require_GET
 @login_required
-def search(request):
+def search(request: HttpRequest) -> HttpResponse:
     """The search.
 
     Args:
-        request (HttpRequest) The request.
+        request: The request.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     # The accounting records
     query = request.GET.get("q")
@@ -809,16 +813,17 @@ class TransactionView(DetailView):
 
 @require_GET
 @login_required
-def txn_form(request, txn_type, txn=None):
+def txn_form(request: HttpRequest, txn_type: str,
+             txn: Transaction = None) -> HttpResponse:
     """The view to edit an accounting transaction.
 
     Args:
-        request (HttpRequest): The request.
+        request: The request.
-        txn_type (str): The transaction type.
+        txn_type: The transaction type.
-        txn (Transaction): The transaction.
+        txn: The transaction.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     previous_post = stored_post.get_previous_post(request)
     if previous_post is not None:
@@ -847,16 +852,17 @@ def txn_form(request, txn_type, txn=None):
 
 @require_POST
 @login_required
-def txn_store(request, txn_type, txn=None):
+def txn_store(request: HttpRequest, txn_type: str,
+              txn: Transaction = None) -> HttpResponseRedirect:
     """The view to store an accounting transaction.
 
     Args:
-        request (HttpRequest): The request.
+        request: The request.
-        txn_type (str): The transaction type.
+        txn_type: The transaction type.
-        txn (Transaction): The transaction.
+        txn: The transaction.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     post = request.POST.dict()
     strip_post(post)
@@ -900,15 +906,15 @@ class TransactionDeleteView(DeleteView):
 
 
 @login_required
-def txn_sort(request, date):
+def txn_sort(request: HttpRequest, date: datetime.date) -> HttpResponse:
     """The view for the form to sort the transactions in a same day.
 
     Args:
-        request (HttpRequest): The request.
+        request: The request.
-        date (datetime.date): The day.
+        date: The day.
 
     Returns:
-        HttpResponse: The response.
+        The response.
 
     Raises:
         Http404: When there are less than two transactions in this day.
@@ -977,15 +983,16 @@ class AccountView(DetailView):
 
 @require_GET
 @login_required
-def account_form(request, account=None):
+def account_form(request: HttpRequest,
+                 account: Account = None) -> HttpResponse:
     """The view to edit an accounting transaction.
 
     Args:
-        request (HttpRequest): The request.
+        request: The request.
-        account (Account): The account.
+        account: The account.
 
     Returns:
-        HttpResponse: The response.
+        The response.
     """
     previous_post = stored_post.get_previous_post(request)
     if previous_post is not None:
@@ -1005,15 +1012,16 @@ def account_form(request, account=None):
 
 @require_POST
 @login_required
-def account_store(request, account=None):
+def account_store(request: HttpRequest,
+                  account: Account = None) -> HttpResponseRedirect:
     """The view to store an account.
 
     Args:
-        request (HttpRequest): The request.
+        request: The request.
-        account (Account): The account.
+        account: The account.
 
     Returns:
-        HttpResponseRedirect: The response.
+        The response.
     """
     post = request.POST.dict()
     strip_post(post)
@@ -1040,7 +1048,8 @@ def account_store(request, account=None):
 
 @require_POST
 @login_required
-def account_delete(request, account):
+def account_delete(request: HttpRequest,
+                   account: Account) -> HttpResponseRedirect:
     """The view to delete an account.
 
     Args:
@@ -1062,28 +1071,28 @@ def account_delete(request, account):
 
 @require_GET
 @login_required
-def api_account_list(request):
+def api_account_list(request: HttpRequest) -> JsonResponse:
     """The API view to return all the accounts.
 
     Args:
-        request (HttpRequest): The request.
+        request: The request.
 
     Returns:
-        JsonResponse: The response.
+        The response.
     """
     return JsonResponse({x.code: x.title for x in Account.objects.all()})
 
 
 @require_GET
 @login_required
-def api_account_options(request):
+def api_account_options(request: HttpRequest) -> JsonResponse:
     """The API view to return the account options.
 
     Args:
-        request (HttpRequest): The request.
+        request: The request.
 
     Returns:
-        JsonResponse: The response.
+        The response.
     """
     accounts = Account.objects\
         .annotate(children_count=Count("child_set"))\