def __init__(self, class_, key, typecallable,
                 dispatch,
                 target_mapper, order_by, query_class=None, **kw):
        super(DynamicAttributeImpl, self).\
            __init__(class_, key, typecallable, dispatch, **kw)
        self.target_mapper = target_mapper
        self.order_by = order_by
        if not query_class:
            self.query_class = AppenderQuery
        elif query_class.mro() in AppenderMixin:
            self.query_class = query_class
        else:
            self.query_class = mixin_user_query(query_class)
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/orm/dynamic.py/DynamicAttributeImpl.__init__/swapped operands of `in`