code: def _retrieve(self, *criterion):
          
          try:
              return self._query(*criterion).one()
          except NoResultFound as error:
              raise ModelNotFoundError(
                  "{} not found".format(
                      self.model_class.__name__,
                  ),
                  error,
              )
docs: Retrieve a model by some criteria.
  
          :raises `ModelNotFoundError` if the row cannot be deleted.