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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 on_shutdown(self, broker):
 """Request the slave gracefully shut itself down."""

        LOG.debug('%r closing CALL_FUNCTION channel', self)
        self._send(
            mitogen.core.Message(
                src_id=mitogen.context_id,
                dst_id=self.remote_id,
                handle=mitogen.core.SHUTDOWN,
            )
        )