def system_methodSignature(self, method_name):

        # See http://xmlrpc.usefulinc.com/doc/sysmethodsig.html

        return 'signatures not supported'
system.methodSignature('add') => [double, int, int]
dataset/ETHPy150Open OpenCobolIDE/OpenCobolIDE/open_cobol_ide/extlibs/future/backports/xmlrpc/server.py/SimpleXMLRPCDispatcher.system_methodSignature