def bbox_shift(bboxes, top, left):
    """shift the bbox
    
    Arguments:
        bboxes {ndarray} -- input bboxes, should be num x 4
        top {int} -- shit to top value, positive mean move down, negative mean move up.
        left {int} -- shit to left value, positive mean move right, negative mean move left.
    
    Returns:
        [ndarray] -- shifted bboxes
    """
    shifted_bboxes = bboxes.copy()
    shifted_bboxes[..., 0::2] = shifted_bboxes[..., 0::2] + left
    shifted_bboxes[..., 1::2] = shifted_bboxes[..., 1::2] + top
    
    return shifted_bboxes