docs: def update_metadata(self, archive_name, archive_metadata):
          '''
          Update metadata for archive ``archive_name``
          '''
  
          required_metadata_keys = self.required_archive_metadata.keys()
          for key, val in archive_metadata.items():
              if key in required_metadata_keys and val is None:
                  raise ValueError(
                      'Cannot remove required metadata attribute "{}"'.format(
                          key))
  
          self._update_metadata(archive_name, archive_metadata)