code: def emails(self, drop_collections = True):
          
          base_df = self._data
          if drop_collections is True:
              out_df = self._drop_collections(base_df)
          else:
              out_df = base_df
          return out_df
docs: Returns a table of mbox message data, with "messages" as rows/observations.
  
          :param bool drop_collections: Defaults to True. Indicates whether columns with lists/dicts/sets will be dropped.
  
          :return: pandas.DataFrame