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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 run(self, *, delay=None):
 """Run the actors in this group. Parameters: delay(int):
 The minimum amount of time, in milliseconds, each message in the group should be delayed by. """

        for child in self.children:
            if isinstance(child, (group, pipeline)):
                child.run(delay=delay)
            else:
                self.broker.enqueue(child, delay=delay)

        return self