code: def json_int_dttm_ser(obj):
      
      val = base_json_conv(obj)
      if val is not None:
          return val
      if isinstance(obj, (datetime, pd.Timestamp)):
          obj = datetime_to_epoch(obj)
      elif isinstance(obj, date):
          obj = (obj - EPOCH.date()).total_seconds() * 1000
      else:
          raise TypeError(
              'Unserializable object {} of type {}'.format(obj, type(obj)))
      return obj
docs: json serializer that deals with dates