def is_derived_from(self, fromclause):
        if self in fromclause._cloned_set:
            return True

        for f in self.locate_all_froms():
            if f.is_derived_from(fromclause):
                return True
        return False
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/sql/selectable.py/Select.is_derived_from/original