<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def complete(self, message, endpoint, return_to):
 """Process the OpenID message, using the specified endpoint and return_to URL as context. This method will handle any OpenID message that is sent to the return_to URL. """

        mode = message.getArg(OPENID_NS, 'mode', '<No mode set>')

        modeMethod = getattr(self, '_complete_' + mode,
                             self._completeInvalid)

        return modeMethod(message, endpoint, return_to)