Update __init__.py

mindspore/nn/loss/__init__.py

@@ -18,7 +18,7 @@ Loss.
 Cells of loss function. Loss function in machine learning is the target of the model.
 It shows how well the model works on a dataset and the optimization target which the optimizer is searching.
 """
-
+#本文件为loss文件构建文件
 from .loss import L1Loss, MSELoss, SmoothL1Loss, FocalLoss,\
     SoftmaxCrossEntropyWithLogits, BCELoss, CosineEmbeddingLoss, \
     SampledSoftmaxLoss, DiceLoss, BCEWithLogitsLoss, MultiClassDiceLoss,\