diff --git a/mmdet/core/losses/__init__.py b/mmdet/core/losses/__init__.py
index 3e4447ff0a6c708e9407bc47698a6281e8c81216..661f0d6426602b5bed7dc3367e1322374922ae1c 100644
--- a/mmdet/core/losses/__init__.py
+++ b/mmdet/core/losses/__init__.py
@@ -1,12 +1,11 @@
-from .losses import (
-    weighted_nll_loss, weighted_cross_entropy, weighted_binary_cross_entropy,
-    sigmoid_focal_loss, weighted_sigmoid_focal_loss, mask_cross_entropy,
-    weighted_mask_cross_entropy, smooth_l1_loss, weighted_smoothl1, accuracy)
+from .losses import (weighted_nll_loss, weighted_cross_entropy,
+                     weighted_binary_cross_entropy, sigmoid_focal_loss,
+                     weighted_sigmoid_focal_loss, mask_cross_entropy,
+                     smooth_l1_loss, weighted_smoothl1, accuracy)
 
 __all__ = [
     'weighted_nll_loss', 'weighted_cross_entropy',
     'weighted_binary_cross_entropy', 'sigmoid_focal_loss',
-    'weighted_sigmoid_focal_loss', 'mask_cross_entropy',
-    'weighted_mask_cross_entropy', 'smooth_l1_loss', 'weighted_smoothl1',
-    'accuracy'
+    'weighted_sigmoid_focal_loss', 'mask_cross_entropy', 'smooth_l1_loss',
+    'weighted_smoothl1', 'accuracy'
 ]