def METHOD_NAME(points, boxes):
    """Find the box in which each point is (CUDA).
    Args:
        points (torch.Tensor): [B, M, 3], [x, y, z] in LiDAR/DEPTH coordinate
        boxes (torch.Tensor): [B, T, 7],
            num_valid_boxes <= T, [x, y, z, x_size, y_size, z_size, rz] in
            LiDAR/DEPTH coordinate, (x, y, z) is the bottom center
    Returns:
        box_idxs_of_pts (torch.Tensor): (B, M), default background = -1
    """
    assert points.shape[0] == boxes.shape[0], \
        'Points and boxes should have the same batch size, ' \
        f'but got {points.shape[0]} and {boxes.shape[0]}'
    assert boxes.shape[2] == 7, \
        'boxes dimension should be 7, ' \
        f'but got unexpected shape {boxes.shape[2]}'
    assert points.shape[2] == 3, \
        'points dimension should be 3, ' \
        f'but got unexpected shape {points.shape[2]}'
    batch_size, num_points, _ = points.shape
    box_idxs_of_pts = points.new_zeros((batch_size, num_points),
                                       dtype=torch.int).fill_(-1)
    # If manually put the tensor 'points' or 'boxes' on a device
    # which is not the current device, some temporary variables
    # will be created on the current device in the cuda op,
    # and the output will be incorrect.
    # Therefore, we force the current device to be the same
    # as the device of the tensors if it was not.
    # Please refer to https://github.com/open-mmlab/mmdetection3d/issues/305
    # for the incorrect output before the fix.
    points_device = points.get_device()
    assert points_device == boxes.get_device(), \
        'Points and boxes should be put on the same device'
    if torch.cuda.current_device() != points_device:
        torch.cuda.set_device(points_device)
    ext_module.points_in_boxes_part_forward(boxes.contiguous(),
                                            points.contiguous(),
                                            box_idxs_of_pts)
    return box_idxs_of_pts