<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def request_job_cancel(self, job_id):
 """ Send a message to the workers to cancel the job with job_id. We then mark the job in the storage as being canceled. :param job_id: the job to cancel :return: None """

        msg = CancelMessage(job_id)
        self.messaging_backend.send(self.worker_mailbox, msg)
        self.storage_backend.mark_job_as_canceling(job_id)