Return the task id associated to the generic source of the signal.

    Args:
        source: source of the signal, it can be either an object id returned
            by a task, a task id, or an actor handle.

    Returns:
        - If source is an object id, return id of task which creted object.
        - If source is an actor handle, return id of actor's task creator.
        - If source is a task id, return same task id.

def _get_task_id(source):
    """Return the task id associated to the generic source of the signal.

    Args:
        source: source of the signal, it can be either an object id returned
            by a task, a task id, or an actor handle.

    Returns:
        - If source is an object id, return id of task which creted object.
        - If source is an actor handle, return id of actor's task creator.
        - If source is a task id, return same task id.
    """
    if type(source) is ray.actor.ActorHandle:
        return source._ray_actor_id
    else:
        if type(source) is ray.TaskID:
            return source
        else:
            return ray._raylet.compute_task_id(source)