fix ci in dev branch (#1264)

mmdet3d/ops/group_points/group_points.py

 # Copyright (c) OpenMMLab. All rights reserved.
+
 from typing import Tuple
 
 import torch

tests/test_models/test_common_modules/test_pointnet_ops.py

@@ -2,16 +2,9 @@
 import pytest
 import torch
 
-from mmdet3d.ops import (
-    ball_query,
-    furthest_point_sample,
-    furthest_point_sample_with_dist,
-    gather_points,
-    grouping_operation,
-    knn,
-    three_interpolate,
-    three_nn,
-)
+from mmdet3d.ops import (ball_query, furthest_point_sample,
+                         furthest_point_sample_with_dist, gather_points,
+                         grouping_operation, knn, three_interpolate, three_nn)
 
 
 def test_fps():