Fix for flake8

examples/instance_segmentation/labelme2voc.py

@@ -7,6 +7,7 @@ import glob
 import json
 import os
 import os.path as osp
+import sys
 
 import numpy as np
 import PIL.Image

examples/semantic_segmentation/labelme2voc.py

@@ -7,6 +7,7 @@ import glob
 import json
 import os
 import os.path as osp
+import sys
 
 import numpy as np
 import PIL.Image