Function ensure_no_pk

lib/sqlalchemy/orm/loading.py:1231–1240

(row)

        # if we are doing polymorphic, dispatch to a different _instance()
        # method specific to the subclass mapper
        def ensure_no_pk(row):
            identitykey = (
                identity_class,
                primary_key_getter(row),
                identity_token,
            )
            if not is_not_primary_key(identitykey[1]):
                return identitykey
            else:
                return None

        _instance = _decorate_polymorphic_switch(
            _instance,