def obj_what_changed(self):
        changes = super(Instance, self).obj_what_changed()
        if 'metadata' in self and self.metadata != self._orig_metadata:
            changes.add('metadata')
        if 'system_metadata' in self and (self.system_metadata !=
                                          self._orig_system_metadata):
            changes.add('system_metadata')
        return changes
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/objects/instance.py/Instance.obj_what_changed/original