<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def send_stun(self, message, addr):
 """ Send a STUN message. """

        self.__log_debug('> %s %s', addr, message)
        self.transport.sendto(bytes(message), addr)