diff --git a/fincal/core.py b/fincal/core.py
index 4f7b698..1f94877 100644
--- a/fincal/core.py
+++ b/fincal/core.py
@@ -16,6 +16,30 @@ class Frequency:
     symbol: str
 
 
+def date_parser(pos, params):
+    def parse_dates(func):
+        def wrapper_func(*args, **kwargs):
+            date_format = kwargs.get("date_format", None)
+            args = list(args)
+            for i, j in enumerate(params):
+                date = kwargs.get(j, None)
+                in_args = False
+                if date is None:
+                    date = args[pos[i]]
+                    in_args = True
+
+                parsed_date = _parse_date(date, date_format)
+                if not in_args:
+                    kwargs[j] = parsed_date
+                else:
+                    args[pos[i]] = parsed_date
+            return func(*args, **kwargs)
+
+        return wrapper_func
+
+    return parse_dates
+
+
 class AllFrequencies:
     D = Frequency("daily", "days", 1, 1, "D")
     W = Frequency("weekly", "days", 7, 7, "W")
@@ -43,23 +67,6 @@ class _IndexSlicer:
         return item
 
 
-def date_parser(*params):
-    def parse_dates(func):
-        def wrapper_func(*args, **kwargs):
-            date_format = kwargs.get('date_format', None)
-
-            for i, j in enumerate(params):
-                date = kwargs.get(j, None)
-                if date is None:
-                    date = args[i+1]
-
-                parsed_date = _parse_date(date, date_format)
-                kwargs[j] = parsed_date
-            return func(**kwargs)
-        return wrapper_func
-    return parse_dates
-
-
 class Series(UserList):
     """Container for a series of objects, all objects must be of the same type"""
 
@@ -238,7 +245,7 @@ class TimeSeriesCore(UserDict):
     def _get_printable_slice(self, n: int):
         """Helper function for __repr__ and __str__
 
-            Returns a slice of the dataframe from beginning and end.
+        Returns a slice of the dataframe from beginning and end.
         """
 
         printable = {}
diff --git a/fincal/fincal.py b/fincal/fincal.py
index 2288752..e3b994b 100644
--- a/fincal/fincal.py
+++ b/fincal/fincal.py
@@ -184,7 +184,7 @@ class TimeSeries(TimeSeriesCore):
 
         return self.__class__(new_ts, frequency=self.frequency.symbol)
 
-    # @date_parser('as_on')
+    @date_parser(pos=[1], params=['as_on'])
     def calculate_returns(
         self,
         as_on: Union[str, datetime.datetime],
@@ -261,7 +261,7 @@ class TimeSeries(TimeSeriesCore):
         (datetime.datetime(2020, 1, 1, 0, 0), .0567)
         """
 
-        as_on = _parse_date(as_on, date_format)
+        # as_on = _parse_date(as_on, date_format)
         as_on_delta, prior_delta = _preprocess_match_options(as_on_match, prior_match, closest)
 
         prev_date = as_on - relativedelta(**{interval_type: interval_value})
@@ -277,7 +277,7 @@ class TimeSeries(TimeSeriesCore):
             returns = returns ** (1 / years)
         return (current[0] if return_actual_date else as_on), returns - 1
 
-    # @date_parser('from_date', 'to_date')
+    @date_parser(pos=[1, 2], params=['from_date', 'to_date'])
     def calculate_rolling_returns(
         self,
         from_date: Union[datetime.date, str],
@@ -358,8 +358,8 @@ class TimeSeries(TimeSeriesCore):
             TimeSeries.calculate_returns
         """
 
-        from_date = _parse_date(from_date, date_format)
-        to_date = _parse_date(to_date, date_format)
+        # from_date = _parse_date(from_date, date_format)
+        # to_date = _parse_date(to_date, date_format)
 
         if frequency is None:
             frequency = self.frequency
diff --git a/fincal/utils.py b/fincal/utils.py
index f031978..e0cb531 100644
--- a/fincal/utils.py
+++ b/fincal/utils.py
@@ -13,7 +13,7 @@ class FincalOptions:
 
 def _parse_date(date: str, date_format: str = None):
     """Parses date and handles errors"""
-
+    # print(date, date_format)
     if isinstance(date, (datetime.datetime, datetime.date)):
         return datetime.datetime.fromordinal(date.toordinal())