def get_all_pending(self, state, dict_):
    if self.key in dict_:
        current = dict_[self.key]
if current is not None:
    ret = [(instance_state(current), current)]
else:
    ret = [(None, None)]
if self.key in state.committed_state:
    original = state.committed_state[self.key]
if original not in (NEVER_SET, PASSIVE_NO_RESULT, None
    ) and original is not current:
    pass
Overriding __cmp__, __eq__, and __hash__ for SQLAlchemy Declarative Base