Remove Python 2 compatibility dependency six

Author: cclauss

test_tipc/supplementary/data.py

@@ -44,9 +44,7 @@ def __init__(self, img_mode="RGB", channel_first=False, **kwargs):
 
     def __call__(self, data):
         img = data["image"]
-        assert (
-            type(img) is bytes and len(img) > 0
-        ), "invalid input 'img' in DecodeImage"
+        assert (type(img) is bytes and len(img) > 0), "invalid input 'img' in DecodeImage"
         img = np.frombuffer(img, dtype="uint8")
         img = cv2.imdecode(img, 1)
         if img is None: