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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 process_callback(self, block=True):
 """Dispatch a single callback in the current thread. :param boolean block: If True, blocks waiting for a callback to come. :return: True if a callback was processed; otherwise False. """

        try:
            (callback, args) = self._queue.get(block=block)
            try:
                callback(*args)
            finally:
                self._queue.task_done()
        except queue.Empty:
            return False
        return True