Remove this worker from the list of available workers.

        This requires the worker to already have been :meth:`register()`.

def unregister(self):
        '''Remove this worker from the list of available workers.

        This requires the worker to already have been :meth:`register()`.

        ''' 
        self.task_master.worker_unregister(self.worker_id)
        self.task_master.worker_id = None
        self.worker_id = None