raise ValueError if exclude_dates is not DatetimeIndex

Author: sharkipelago

pandas/tseries/holiday.py

@@ -260,7 +260,8 @@ class from pandas.tseries.offsets, default None
         self.observance = observance
         assert days_of_week is None or type(days_of_week) == tuple
         self.days_of_week = days_of_week
-        assert exclude_dates is None or type(exclude_dates) == DatetimeIndex
+        if exclude_dates is not None and type(exclude_dates) != DatetimeIndex:
+            raise ValueError("exclude_dates must be None or of type DatetimeIndex.")
         self.exclude_dates = exclude_dates
 
     def __repr__(self) -> str: