diff --git a/fincal/core.py b/fincal/core.py
index 4cd8836..4f7b698 100644
--- a/fincal/core.py
+++ b/fincal/core.py
@@ -43,6 +43,23 @@ 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"""
 
@@ -157,7 +174,7 @@ class TimeSeriesCore(UserDict):
     def __init__(
         self, data: List[Iterable], frequency: Literal["D", "W", "M", "Q", "H", "Y"], date_format: str = "%Y-%m-%d"
     ):
-        """Instantiate a TimeSeries object
+        """Instantiate a TimeSeriesCore object
 
         Parameters
         ----------
diff --git a/fincal/fincal.py b/fincal/fincal.py
index 7c84cf5..2288752 100644
--- a/fincal/fincal.py
+++ b/fincal/fincal.py
@@ -5,7 +5,7 @@ from typing import Iterable, List, Literal, Mapping, Union
 
 from dateutil.relativedelta import relativedelta
 
-from .core import AllFrequencies, TimeSeriesCore
+from .core import AllFrequencies, TimeSeriesCore, date_parser
 from .utils import (
     _find_closest_date,
     _interval_to_years,
@@ -184,6 +184,7 @@ class TimeSeries(TimeSeriesCore):
 
         return self.__class__(new_ts, frequency=self.frequency.symbol)
 
+    # @date_parser('as_on')
     def calculate_returns(
         self,
         as_on: Union[str, datetime.datetime],
@@ -276,6 +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')
     def calculate_rolling_returns(
         self,
         from_date: Union[datetime.date, str],