docs: def mlt(self, _id):
          '''
          High-level method to do "more like this".
  
          Its exact implementation can vary.
          '''
          query = {
              'query': {'more_like_this': {
                        'like': {'_id': _id},
                        'min_term_freq': 1,
                        'min_doc_freq': 1,
               }}
          }
          if es_version[0] <= 1:
              mlt = query['query']['more_like_this']
              mlt['ids'] = [_id]
              del mlt['like']
          return self._search(query)