'Tell all (or specific) workers to revoke a task by id.
If a task is revoked, the workers will ignore the task and
not execute it after all.
Arguments:
task_id (str): Id of the task to revoke.
terminate (bool): Also terminate the process currently working
on the task (if any).
signal (str): Name of signal to send to process if terminate.
Default is TERM.
See Also:
:meth:`broadcast` for supported keyword arguments.'

def revoke(self, task_id, destination=None, terminate=False, signal=TERM_SIGNAME, **kwargs):

    return self.broadcast(u'revoke', destination=destination, arguments={u'task_id': task_id, u'terminate': terminate, u'signal': signal}, **kwargs)
