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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:
 async def on_raw_433(self, message):
 """ Nickname in use. """

        if not self.registered:
            self._registration_attempts += 1
            # Attempt to set new nickname.
            if self._attempt_nicknames:
                await self.set_nickname(self._attempt_nicknames.pop(0))
            else:
                await self.set_nickname(
                    self._nicknames[0] + '_' * (self._registration_attempts - len(self._nicknames)))