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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 accept(self, timeout=None):
 """ Return the next channel opened by the client over this transport, in server mode. If no channel is opened before the given timeout, ``None`` is returned. :param int timeout: seconds to wait for a channel, or ``None`` to wait forever :return: a new `.Channel` opened by the client """

        self.lock.acquire()
        try:
            if len(self.server_accepts) > 0:
                chan = self.server_accepts.pop(0)
            else:
                self.server_accept_cv.wait(timeout)
                if len(self.server_accepts) > 0:
                    chan = self.server_accepts.pop(0)
                else:
                    # timeout
                    chan = None
        finally:
            self.lock.release()
        return chan