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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:
 async def set_update_cb(self, cb):
 """Register the update callback."""

        if self._report_task is not None and not self._report_task.cancelled():
            self.loop.create_task(self._report_task.cancel())
        self._update_cb = cb
        if cb is not None:
            self._report_task = self.loop.create_task(self._report())