docs: def to_mongo(self, range_obj):
          """
          takes the range object used for this chunker type
          and converts it into a string that can be use for a
          mongo query that filters by the range
  
          returns
          -------
          dict
          """
          if isinstance(range_obj, (pd.DatetimeIndex, tuple)):
              range_obj = DateRange(range_obj[0], range_obj[-1])
          if range_obj.start and range_obj.end:
              return {'$and': [{START: {'$lte': range_obj.end}}, {END: {'$gte': range_obj.start}}]}
          elif range_obj.start:
              return {END: {'$gte': range_obj.start}}
          elif range_obj.end:
              return {START: {'$lte': range_obj.end}}
          else:
              return {}