code: def _phrase_query(self, term_list, field_name, field_type):
          
          term_list = [self._term_query(term, field_name, field_type,
                                        stemmed=False) for term in term_list]
  
          query = xapian.Query(xapian.Query.OP_PHRASE, term_list)
          return query
docs: Returns a query that matches exact terms with
          positional order (i.e. ["this", "thing"] != ["thing", "this"])
          and no stem.
  
          If `field_name` is not `None`, restrict to the field.