def symmetric_difference_update(self, other):
        set.symmetric_difference_update(self, other)
        self._list = [a for a in self._list if a in self]
        self._list += [a for a in other._list if self in a]
        return self
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/util/_collections.py/OrderedSet.symmetric_difference_update/swapped operands of `in`