code: def match_one(self, models, results, relation):
          
          return self._match_one_or_many(models, results, relation, 'one')
docs: Match the eargerly loaded resuls to their single parents.
  
          :param models: The parents
          :type models: list
  
          :param results: The results collection
          :type results: Collection
  
          :param relation: The relation
          :type relation: str
  
          :rtype: list