diff --git a/imperative/python/megengine/functional/nn.py b/imperative/python/megengine/functional/nn.py
index 4bed60525e75c0a61cc314b7432641b1f3ab3ee5..2e1a6221ffa6719ecc435e03d82800e4fc95c737 100644
--- a/imperative/python/megengine/functional/nn.py
+++ b/imperative/python/megengine/functional/nn.py
@@ -1188,7 +1188,7 @@ def general_norm(
         sorted(normalized_axis), normalized_axis
     )
     assert (
-        normalized_axis[-1] < inp.ndim,
+        normalized_axis[-1] < inp.ndim
     ), "the maximum axis in normalized_axis is greater than inp_shape.ndim"
     assert len(set(normalized_axis)) == len(
         normalized_axis