def getExtensionArgs(self):
        """Get a dictionary of unqualified simple registration
        arguments representing this request.

        This method is essentially the inverse of
        C{L{parseExtensionArgs}}. This method serializes the simple
        registration request fields.

        @rtype: {str:str}
        """
        args = {}

        if self.required:
            args['required'] = ','.join(self.required)

        if self.optional:
            args['optional'] = ','.join(self.optional)

        if self.policy_url:
            args['policy_url'] = self.policy_url

        return args