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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def toMessage(self):
 """Generate a Message object for sending to the relying party, after encoding. """

        namespace = self.openid_message.getOpenIDNamespace()
        reply = Message(namespace)
        reply.setArg(OPENID_NS, 'mode', 'error')
        reply.setArg(OPENID_NS, 'error', str(self))

        if self.contact is not None:
            reply.setArg(OPENID_NS, 'contact', str(self.contact))

        if self.reference is not None:
            reply.setArg(OPENID_NS, 'reference', str(self.reference))

        return reply