docs: def _get_archive_listing(self, archive_name):
          '''
          Return full document for ``{_id:'archive_name'}``
  
          .. note::
  
              MongoDB specific results - do not expose to user
          '''
  
          res = self.collection.find_one({'_id': archive_name})
  
          if res is None:
              raise KeyError
  
          return res