'Shortcut for doing an UPDATE on this object.
If _signal=False is in ``kw`` the post_save signal won\'t be sent.'

def update(self, **kw):

    signal = kw.pop('_signal', True)
    old_attr = dict(self.__dict__)
    result = super(OnChangeMixin, self).update(_signal=signal, **kw)
    if (signal and (self.__class__ in _on_change_callbacks)):
        self._send_changes(old_attr, kw)
    return result
