docs: def get_start_date_metadata(self):
          """Gets the metadata for a start date.
  
          return: (osid.Metadata) - metadata for the date
          *compliance: mandatory -- This method must be implemented.*
  
          """
          metadata = dict(self._mdata['start_date'])
          metadata.update({'existing_date_time_values': self._my_map['startDate']})
          return Metadata(**metadata)