diff --git a/src/accounting/forms.py b/src/accounting/forms.py
index 026130f..7aa5e28 100644
--- a/src/accounting/forms.py
+++ b/src/accounting/forms.py
@@ -53,14 +53,11 @@ class AccountExists:
 class IsDebitAccount:
     """The validator to check if the account is for debit line items."""
 
-    def __init__(self, message: str | LazyString | None = None):
+    def __init__(self, message: str | LazyString):
         """Constructs the validator.
 
-        :param message: The optional custom error message.
+        :param message: The error message.
         """
-        if message is None:
-            message = lazy_gettext(
-                "This account is not for debit line items.")
         self.__message: str | LazyString = message
 
     def __call__(self, form: FlaskForm, field: StringField) -> None:
@@ -76,14 +73,11 @@ class IsDebitAccount:
 class IsCreditAccount:
     """The validator to check if the account is for credit line items."""
 
-    def __init__(self, message: str | LazyString | None = None):
+    def __init__(self, message: str | LazyString):
         """Constructs the validator.
 
-        :param message: The optional custom error message.
+        :param message: The error message.
         """
-        if message is None:
-            message = lazy_gettext(
-                "This account is not for credit line items.")
         self.__message: str | LazyString = message
 
     def __call__(self, form: FlaskForm, field: StringField) -> None:
diff --git a/src/accounting/journal_entry/forms/line_item.py b/src/accounting/journal_entry/forms/line_item.py
index ddf198b..0f4cf37 100644
--- a/src/accounting/journal_entry/forms/line_item.py
+++ b/src/accounting/journal_entry/forms/line_item.py
@@ -413,12 +413,14 @@ class DebitLineItemForm(LineItemForm):
     """The ID of the original line item."""
     account_code = StringField(
         filters=[strip_text],
-        validators=[ACCOUNT_REQUIRED,
-                    AccountExists(),
-                    IsDebitAccount(),
-                    SameAccountAsOriginalLineItem(),
-                    KeepAccountWhenHavingOffset(),
-                    NotStartPayableFromDebit()])
+        validators=[
+            ACCOUNT_REQUIRED,
+            AccountExists(),
+            IsDebitAccount(lazy_gettext(
+                "This account is not for debit line items.")),
+            SameAccountAsOriginalLineItem(),
+            KeepAccountWhenHavingOffset(),
+            NotStartPayableFromDebit()])
     """The account code."""
     description = StringField(filters=[strip_text])
     """The description."""
@@ -463,12 +465,14 @@ class CreditLineItemForm(LineItemForm):
     """The ID of the original line item."""
     account_code = StringField(
         filters=[strip_text],
-        validators=[ACCOUNT_REQUIRED,
-                    AccountExists(),
-                    IsCreditAccount(),
-                    SameAccountAsOriginalLineItem(),
-                    KeepAccountWhenHavingOffset(),
-                    NotStartReceivableFromCredit()])
+        validators=[
+            ACCOUNT_REQUIRED,
+            AccountExists(),
+            IsCreditAccount(lazy_gettext(
+                "This account is not for credit line items.")),
+            SameAccountAsOriginalLineItem(),
+            KeepAccountWhenHavingOffset(),
+            NotStartReceivableFromCredit()])
     """The account code."""
     description = StringField(filters=[strip_text])
     """The description."""