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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 start(self, build_requests=None, callback=None):
 """ Run the client using a background thread. """

        if callback:
            self.callback = callback
        if build_requests:
            self.build_requests = build_requests

        # spin off requester thread
        self.sw = threading.Thread(target=self.run)
        self.sw.start()