@util.memoized_property
    def _cloned_set(self):
        s = util.column_set()
        f = self
        while f is not None:
            s.add(f)
            f = f._is_clone_of
        return s
Return the set consisting all cloned ancestors of this
dataset/ETHPy150Open goFrendiAsgard/kokoropy/kokoropy/packages/sqlalchemy/sql/elements.py/ClauseElement._cloned_set