def xmlrpc_defer(self, x):
        return defer.succeed(x)
https://familysearch.org/developers/docs/api/tree/Couple_Relationship_Change_History_resource
dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/web/test/test_xmlrpc.py/Test.xmlrpc_defer--crossover with--dataset/ETHPy150Open AmEv7Fam/familysearch-python-sdk-opensource/familysearch/changeHistory.py/ChangeHistory.couple_change_history