'Return a list of type signatures.
Each type signature is a list of the form [rtype, type1, type2, ...]
where rtype is the return type and typeN is the type of the Nth
argument. If no signature information is available, the empty
string is returned.'

def xmlrpc_methodSignature(self, method):

    method = self._xmlrpc_parent.lookupProcedure(method)
    return (getattr(method, 'signature', None) or '')
