Update loss.py

python/paddle/nn/functional/loss.py

@@ -1806,8 +1806,8 @@ def cross_entropy(input,
 
             valid_label = paddle.where(label == ignore_index,
                                        paddle.zeros_like(label), label)
-            ignore_weight_mask = paddle.cast(
-                (label != ignore_index), input.dtype)
+            ignore_weight_mask = paddle.cast((label != ignore_index),
+                                             input.dtype)
             if ignore_weight_mask.ndim > 1 and ignore_weight_mask.shape[
                     -1] == 1:
                 ignore_weight_mask = paddle.squeeze(ignore_weight_mask, -1)