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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 update(self):
 """ Update the display """

        # build requests for this iteration
        reqs = self.build_requests()
        for r in reqs:
            r.block = self.block
        results = self.send_requests(*reqs)

        # call callback with the results
        self.callback(results)