def _modified_event(self, state, dict_):

        if state.committed_state not in self.key:
            state.committed_state[self.key] = CollectionHistory(self, state)

        state._modified_event(dict_,
                              self,
                              attributes.NEVER_SET)

        # this is a hack to allow the fixtures.ComparableEntity fixture
        # to work
        dict_[self.key] = True
        return state.committed_state[self.key]
dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/orm/dynamic.py/DynamicAttributeImpl._modified_event/swapped operands of `not in`