diff --git a/accounting/utils.py b/accounting/utils.py
index e3ef052..2c881df 100644
--- a/accounting/utils.py
+++ b/accounting/utils.py
@@ -34,7 +34,7 @@ class ReportUrl:
         if "period" in kwargs:
             self._period = kwargs["period"]
         else:
-            self._period = Period(None, None, None, None)
+            self._period = Period()
         if "cash" in kwargs:
             self._cash_subject = kwargs["cash"]
         else:
diff --git a/accounting/views/__init__.py b/accounting/views/__init__.py
index 35c42de..13059ec 100644
--- a/accounting/views/__init__.py
+++ b/accounting/views/__init__.py
@@ -74,8 +74,7 @@ def cash(request, subject_code, period_spec):
     last_txn = Transaction.objects.order_by("-date").first()
     data_end = last_txn.date if last_txn is not None else None
     period = Period(
-        get_language(), data_start, data_end,
-        period_spec)
+        period_spec, data_start, data_end, get_language())
     # The SQL query
     if subject_code == "0":
         subject = Subject(code="0")
diff --git a/mia_core/period.py b/mia_core/period.py
index 86ed767..b7e6f00 100644
--- a/mia_core/period.py
+++ b/mia_core/period.py
@@ -33,10 +33,10 @@ class Period:
     """The template helper for the period chooser.
 
     Args:
-        language (str|None): The current language.
-        data_start (date|None): The available first day of the data.
-        data_end (date|None): The available last day of the data.
-        spec (str|None): The current period specification
+        spec (str): The current period specification
+        data_start (date): The available first day of the data.
+        data_end (date): The available last day of the data.
+        language (str): The current language.
 
     Attributes:
         spec (date): The currently-working period specification.
@@ -82,11 +82,13 @@ class Period:
     _data_end = None
     _period = None
 
-    def __init__(self, language, data_start, data_end, spec):
-        self._language = language
+    def __init__(
+            self, spec = None,
+            data_start = None, data_end = None, language = None):
+        self._period = self.Parser(spec)
         self._data_start = data_start
         self._data_end = data_end
-        self._period = self.Parser(spec)
+        self._language = language
 
     @property
     def spec(self):