def _unset_expiration_date_time(self):
    self.__expiration_date_time = YANGDynClass(base=[RestrictedClassType(base_type=six.text_type, restriction_dict={'pattern': '[0-9]{4}\\-(0[1-9]|1[0-2])\\-(0[1-9]|[12][0-9]|3[01])[Tt](0[0-9]|1[0-9]|2[0-3]):(0[0-9]|[1-5][0-9]):(0[0-9]|[1-5][0-9]|60)(\\.[0-9]+)?([Zz]|([+-](0[0-9]|1[0-9]|2[0-3]):(0[0-9]|[1-5][0-9])))'}),RestrictedClassType(base_type=six.text_type,                                     restriction_type="dict_key",                                     restriction_arg={'NO_EXPIRATION': {}},),], default=six.text_type("NO_EXPIRATION"), is_leaf=True, yang_name="expiration-date-time", parent=self, path_helper=self._path_helper, extmethods=self._extmethods, register_paths=True, namespace='http://openconfig.net/yang/macsec', defining_module='openconfig-macsec', yang_type='union', is_config=True)