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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 wait(self, *, block=True, timeout=None):
 """Signal that a party has reached the barrier. Warning: Barrier blocking is currently only supported by the stub and Redis backends. Warning: Re-using keys between blocking calls may lead to undefined behaviour. Make sure your barrier keys are always unique (use a UUID). Parameters: block(bool):
 Whether or not to block while waiting for the other parties. timeout(int):
 The maximum number of milliseconds to wait for the barrier to be cleared. Returns: bool: Whether or not the barrier has been reached by all parties. """

        cleared = not self.backend.decr(self.key, 1, 1, self.ttl)
        if cleared:
            self.backend.wait_notify(self.key_events, self.ttl)
            return True

        if block:
            return self.backend.wait(self.key_events, timeout)

        return False