def on_model_changed(sender, **kwargs): record_trail('change', kwargs.get('instance', None), kwargs.get('changes', {}))
def on_model_deleted(sender, **kwargs): record_trail('delete', kwargs.get('instance', None))
def on_model_added(sender, **kwargs): record_trail('add', kwargs.get('instance', None), serialize_instance(kwargs.get('instance')))