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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 _send_one(self, stream, handle, target_id, name):
 """ Compose and send an update message on a stream. :param mitogen.core.Stream stream: Stream to send it on. :param int handle: :data:`mitogen.core.ADD_ROUTE` or :data:`mitogen.core.DEL_ROUTE` :param int target_id: ID of the connecting or disconnecting context. :param str name: Context name or :data:`None`. """

        if not stream:
            # We may not have a stream during shutdown.
            return

        data = str(target_id)
        if name:
            data = '%s:%s' % (target_id, name)
        stream.send(
            mitogen.core.Message(
                handle=handle,
                data=data.encode('utf-8'),
                dst_id=stream.remote_id,
            )
        )