diff --git a/deploy/pdserving/README.md b/deploy/pdserving/README.md
index de7965bac752f6bc9cd1de224b791b0a84f0e699..cb2845c581d244e80ca597e0eb485a16ad369f20 100644
--- a/deploy/pdserving/README.md
+++ b/deploy/pdserving/README.md
@@ -114,7 +114,7 @@ The recognition model is the same.
     git clone https://github.com/PaddlePaddle/PaddleOCR
 
     # Enter the working directory  
-    cd PaddleOCR/deploy/pdserver/
+    cd PaddleOCR/deploy/pdserving/
     ```
 
     The pdserver directory contains the code to start the pipeline service and send prediction requests, including:
diff --git a/deploy/pdserving/README_CN.md b/deploy/pdserving/README_CN.md
index 5106fd9b2d03e6169cf0c723b241cb1385a22906..067be8bbda10d971b709afdf822aea96a979d000 100644
--- a/deploy/pdserving/README_CN.md
+++ b/deploy/pdserving/README_CN.md
@@ -112,7 +112,7 @@ python3 -m paddle_serving_client.convert --dirname ./ch_ppocr_mobile_v2.0_rec_in
     git clone https://github.com/PaddlePaddle/PaddleOCR
 
     # 进入到工作目录
-    cd PaddleOCR/deploy/pdserver/
+    cd PaddleOCR/deploy/pdserving/
     ```
     pdserver目录包含启动pipeline服务和发送预测请求的代码，包括：
     ```
@@ -206,7 +206,7 @@ pip3 install paddle-serving-app==0.3.1
 1. 启动服务端程序
 
 ```
-cd win 
+cd win
 python3 ocr_web_server.py gpu(使用gpu方式)
 或者
 python3 ocr_web_server.py cpu(使用cpu方式)
diff --git a/ppocr/data/imaug/iaa_augment.py b/ppocr/data/imaug/iaa_augment.py
index 9ce6bd4209034389df04334a83717142ca8c7b40..0aac7877c257f3e7532ca2806891775913d416b7 100644
--- a/ppocr/data/imaug/iaa_augment.py
+++ b/ppocr/data/imaug/iaa_augment.py
@@ -11,6 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/WenmuZhou/DBNet.pytorch/blob/master/data_loader/modules/iaa_augment.py
+"""
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
diff --git a/ppocr/data/imaug/make_border_map.py b/ppocr/data/imaug/make_border_map.py
index cc2c9034e147eb7bb6a70e43eda4903337a523f0..abab38368db2de84e54b060598fc509a65219296 100644
--- a/ppocr/data/imaug/make_border_map.py
+++ b/ppocr/data/imaug/make_border_map.py
@@ -1,4 +1,20 @@
-# -*- coding:utf-8 -*- 
+# copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+This code is refer from:
+https://github.com/WenmuZhou/DBNet.pytorch/blob/master/data_loader/modules/make_border_map.py
+"""
 
 from __future__ import absolute_import
 from __future__ import division
diff --git a/ppocr/data/imaug/make_pse_gt.py b/ppocr/data/imaug/make_pse_gt.py
index 55abc8970784fd00843d2e91f259c58b65ae8579..255d076bde848d53f3b2fb04e80594872f4ae8c7 100644
--- a/ppocr/data/imaug/make_pse_gt.py
+++ b/ppocr/data/imaug/make_pse_gt.py
@@ -1,4 +1,16 @@
-# -*- coding:utf-8 -*- 
+# copyright (c) 2021 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
 from __future__ import absolute_import
 from __future__ import division
@@ -12,12 +24,8 @@ from shapely.geometry import Polygon
 
 __all__ = ['MakePseGt']
 
-class MakePseGt(object):
-    r'''
-    Making binary mask from detection data with ICDAR format.
-    Typically following the process of class `MakeICDARData`.
-    '''
 
+class MakePseGt(object):
     def __init__(self, kernel_num=7, size=640, min_shrink_ratio=0.4, **kwargs):
         self.kernel_num = kernel_num
         self.min_shrink_ratio = min_shrink_ratio
@@ -38,16 +46,20 @@ class MakePseGt(object):
             text_polys *= scale
 
         gt_kernels = []
-        for i in range(1,self.kernel_num+1):
+        for i in range(1, self.kernel_num + 1):
             # s1->sn, from big to small
-            rate = 1.0 - (1.0 - self.min_shrink_ratio) / (self.kernel_num - 1) * i
-            text_kernel, ignore_tags = self.generate_kernel(image.shape[0:2], rate, text_polys, ignore_tags)
+            rate = 1.0 - (1.0 - self.min_shrink_ratio) / (self.kernel_num - 1
+                                                          ) * i
+            text_kernel, ignore_tags = self.generate_kernel(
+                image.shape[0:2], rate, text_polys, ignore_tags)
             gt_kernels.append(text_kernel)
 
         training_mask = np.ones(image.shape[0:2], dtype='uint8')
         for i in range(text_polys.shape[0]):
             if ignore_tags[i]:
-                cv2.fillPoly(training_mask, text_polys[i].astype(np.int32)[np.newaxis, :, :], 0)
+                cv2.fillPoly(training_mask,
+                             text_polys[i].astype(np.int32)[np.newaxis, :, :],
+                             0)
 
         gt_kernels = np.array(gt_kernels)
         gt_kernels[gt_kernels > 0] = 1
@@ -59,16 +71,25 @@ class MakePseGt(object):
         data['mask'] = training_mask.astype('float32')
         return data
 
-    def generate_kernel(self, img_size, shrink_ratio, text_polys, ignore_tags=None):
+    def generate_kernel(self,
+                        img_size,
+                        shrink_ratio,
+                        text_polys,
+                        ignore_tags=None):
+        """
+        Refer to part of the code:
+        https://github.com/open-mmlab/mmocr/blob/main/mmocr/datasets/pipelines/textdet_targets/base_textdet_targets.py
+        """
+
         h, w = img_size
         text_kernel = np.zeros((h, w), dtype=np.float32)
         for i, poly in enumerate(text_polys):
             polygon = Polygon(poly)
-            distance = polygon.area * (1 - shrink_ratio * shrink_ratio) / (polygon.length + 1e-6)
+            distance = polygon.area * (1 - shrink_ratio * shrink_ratio) / (
+                polygon.length + 1e-6)
             subject = [tuple(l) for l in poly]
             pco = pyclipper.PyclipperOffset()
-            pco.AddPath(subject, pyclipper.JT_ROUND,
-                        pyclipper.ET_CLOSEDPOLYGON)
+            pco.AddPath(subject, pyclipper.JT_ROUND, pyclipper.ET_CLOSEDPOLYGON)
             shrinked = np.array(pco.Execute(-distance))
 
             if len(shrinked) == 0 or shrinked.size == 0:
diff --git a/ppocr/data/imaug/make_shrink_map.py b/ppocr/data/imaug/make_shrink_map.py
index 15e8afa05bb9f7315a2e9342c78cb98718a54df9..6c65c20e5621f91a5b1fba549b059c92923fca6f 100644
--- a/ppocr/data/imaug/make_shrink_map.py
+++ b/ppocr/data/imaug/make_shrink_map.py
@@ -1,4 +1,20 @@
-# -*- coding:utf-8 -*- 
+# copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+This code is refer from:
+https://github.com/WenmuZhou/DBNet.pytorch/blob/master/data_loader/modules/make_shrink_map.py
+"""
 
 from __future__ import absolute_import
 from __future__ import division
diff --git a/ppocr/data/imaug/random_crop_data.py b/ppocr/data/imaug/random_crop_data.py
index 7c1c25abb56a0cf7d4d59b8523962bd5d81c873a..64aa110de4e3df950ce21e6d657877081b0fdd13 100644
--- a/ppocr/data/imaug/random_crop_data.py
+++ b/ppocr/data/imaug/random_crop_data.py
@@ -1,4 +1,20 @@
-# -*- coding:utf-8 -*- 
+# copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+This code is refer from:
+https://github.com/WenmuZhou/DBNet.pytorch/blob/master/data_loader/modules/random_crop_data.py
+"""
 
 from __future__ import absolute_import
 from __future__ import division
diff --git a/ppocr/data/imaug/text_image_aug/augment.py b/ppocr/data/imaug/text_image_aug/augment.py
index 1aeff3733a4521c56dd5972fc058f6e0c245e4b7..2d15dd5f353c72a6cc3876481c423d81a8175c95 100644
--- a/ppocr/data/imaug/text_image_aug/augment.py
+++ b/ppocr/data/imaug/text_image_aug/augment.py
@@ -11,6 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/RubanSeven/Text-Image-Augmentation-python/blob/master/augment.py
+"""
 
 import numpy as np
 from .warp_mls import WarpMLS
diff --git a/ppocr/data/imaug/text_image_aug/warp_mls.py b/ppocr/data/imaug/text_image_aug/warp_mls.py
index d6cbe749b61aa4cf3163927c096868c83f4a4cdd..75de11115cf9ba824a7cd62b8b880ea7f99e4cb2 100644
--- a/ppocr/data/imaug/text_image_aug/warp_mls.py
+++ b/ppocr/data/imaug/text_image_aug/warp_mls.py
@@ -11,6 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/RubanSeven/Text-Image-Augmentation-python/blob/master/warp_mls.py
+"""
 
 import numpy as np
 
@@ -161,4 +165,4 @@ class WarpMLS:
         dst = np.clip(dst, 0, 255)
         dst = np.array(dst, dtype=np.uint8)
 
-        return dst
\ No newline at end of file
+        return dst
diff --git a/ppocr/losses/ace_loss.py b/ppocr/losses/ace_loss.py
index bf15f8e3a7b355bd9e8b69435a5dae01fc75a892..915b99e6ec1d6cb4641d8032fa188c61006dfbb3 100644
--- a/ppocr/losses/ace_loss.py
+++ b/ppocr/losses/ace_loss.py
@@ -11,6 +11,9 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+# This code is refer from: https://github.com/viig99/LS-ACELoss
+
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
@@ -32,7 +35,7 @@ class ACELoss(nn.Layer):
     def __call__(self, predicts, batch):
         if isinstance(predicts, (list, tuple)):
             predicts = predicts[-1]
-            
+
         B, N = predicts.shape[:2]
         div = paddle.to_tensor([N]).astype('float32')
 
diff --git a/ppocr/losses/center_loss.py b/ppocr/losses/center_loss.py
index cbef4df965e2659c6aa63c0c69cd8798143df485..f8c57fdd5c9b3f0dec5c3d0a811e5532abd2e45a 100644
--- a/ppocr/losses/center_loss.py
+++ b/ppocr/losses/center_loss.py
@@ -12,6 +12,8 @@
 #See the License for the specific language governing permissions and
 #limitations under the License.
 
+# This code is refer from: https://github.com/KaiyangZhou/pytorch-center-loss
+
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
@@ -27,6 +29,7 @@ class CenterLoss(nn.Layer):
     """
     Reference: Wen et al. A Discriminative Feature Learning Approach for Deep Face Recognition. ECCV 2016.
     """
+
     def __init__(self,
                  num_classes=6625,
                  feat_dim=96,
diff --git a/ppocr/losses/det_basic_loss.py b/ppocr/losses/det_basic_loss.py
index 7017236c284e55710f242275a413d56d32158d34..61ea579b41d3cdf7831c168f563a1e3cd72463a0 100644
--- a/ppocr/losses/det_basic_loss.py
+++ b/ppocr/losses/det_basic_loss.py
@@ -11,7 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+"""
+This code is refer from:
+https://github.com/WenmuZhou/DBNet.pytorch/blob/master/models/losses/basic_loss.py
+"""
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
@@ -147,4 +150,4 @@ class BCELoss(nn.Layer):
 
     def forward(self, input, label, mask=None, weight=None, name=None):
         loss = F.binary_cross_entropy(input, label, reduction=self.reduction)
-        return loss
\ No newline at end of file
+        return loss
diff --git a/ppocr/losses/det_db_loss.py b/ppocr/losses/det_db_loss.py
index b079aabff7c7deccc7e365b91c9407f7e894bcb9..708ffbdb47f349304e2bfd781a836e79348475f4 100755
--- a/ppocr/losses/det_db_loss.py
+++ b/ppocr/losses/det_db_loss.py
@@ -11,6 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/WenmuZhou/DBNet.pytorch/blob/master/models/losses/DB_loss.py
+"""
 
 from __future__ import absolute_import
 from __future__ import division
diff --git a/ppocr/losses/det_pse_loss.py b/ppocr/losses/det_pse_loss.py
index 78423091f841f29b1217f73f79beb26fe1575844..9b8ac4b5a5dfac176c398dd0a9e490e5ca67ad5f 100644
--- a/ppocr/losses/det_pse_loss.py
+++ b/ppocr/losses/det_pse_loss.py
@@ -11,6 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/whai362/PSENet/blob/python3/models/head/psenet_head.py
+"""
 
 import paddle
 from paddle import nn
diff --git a/ppocr/modeling/backbones/rec_mv1_enhance.py b/ppocr/modeling/backbones/rec_mv1_enhance.py
index 04a909b8ccafd8e62f9a7076c7dedf63ff745303..d8a7f4b5646eb70b5202aa3b3ac6494318b424ad 100644
--- a/ppocr/modeling/backbones/rec_mv1_enhance.py
+++ b/ppocr/modeling/backbones/rec_mv1_enhance.py
@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# This code is refer from: https://github.com/PaddlePaddle/PaddleClas/blob/develop/ppcls/arch/backbone/legendary_models/pp_lcnet.py
+
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
diff --git a/ppocr/modeling/backbones/rec_resnet_31.py b/ppocr/modeling/backbones/rec_resnet_31.py
index f60729cdcced2af7626e5615ca323e32c99432ec..965170138d00a53fca720b3b5f535a3dd34272d9 100644
--- a/ppocr/modeling/backbones/rec_resnet_31.py
+++ b/ppocr/modeling/backbones/rec_resnet_31.py
@@ -1,3 +1,22 @@
+# copyright (c) 2021 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+This code is refer from: 
+https://github.com/open-mmlab/mmocr/blob/main/mmocr/models/textrecog/layers/conv_layer.py
+https://github.com/open-mmlab/mmocr/blob/main/mmocr/models/textrecog/backbones/resnet31_ocr.py
+"""
+
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
@@ -18,12 +37,12 @@ def conv3x3(in_channel, out_channel, stride=1):
         kernel_size=3,
         stride=stride,
         padding=1,
-        bias_attr=False
-    )
+        bias_attr=False)
 
 
 class BasicBlock(nn.Layer):
     expansion = 1
+
     def __init__(self, in_channels, channels, stride=1, downsample=False):
         super().__init__()
         self.conv1 = conv3x3(in_channels, channels, stride)
@@ -34,9 +53,13 @@ class BasicBlock(nn.Layer):
         self.downsample = downsample
         if downsample:
             self.downsample = nn.Sequential(
-                nn.Conv2D(in_channels, channels * self.expansion, 1, stride, bias_attr=False),
-                nn.BatchNorm2D(channels * self.expansion),
-            )
+                nn.Conv2D(
+                    in_channels,
+                    channels * self.expansion,
+                    1,
+                    stride,
+                    bias_attr=False),
+                nn.BatchNorm2D(channels * self.expansion), )
         else:
             self.downsample = nn.Sequential()
         self.stride = stride
@@ -57,7 +80,7 @@ class BasicBlock(nn.Layer):
         out += residual
         out = self.relu(out)
 
-        return out        
+        return out
 
 
 class ResNet31(nn.Layer):
@@ -69,12 +92,13 @@ class ResNet31(nn.Layer):
         out_indices (None | Sequence[int]): Indices of output stages.
         last_stage_pool (bool): If True, add `MaxPool2d` layer to last stage.
     '''
-    def __init__(self, 
-                in_channels=3, 
-                layers=[1, 2, 5, 3],
-                channels=[64, 128, 256, 256, 512, 512, 512],
-                out_indices=None,
-                last_stage_pool=False):
+
+    def __init__(self,
+                 in_channels=3,
+                 layers=[1, 2, 5, 3],
+                 channels=[64, 128, 256, 256, 512, 512, 512],
+                 out_indices=None,
+                 last_stage_pool=False):
         super(ResNet31, self).__init__()
         assert isinstance(in_channels, int)
         assert isinstance(last_stage_pool, bool)
@@ -83,46 +107,56 @@ class ResNet31(nn.Layer):
         self.last_stage_pool = last_stage_pool
 
         # conv 1 (Conv Conv)
-        self.conv1_1 = nn.Conv2D(in_channels, channels[0], kernel_size=3, stride=1, padding=1)
+        self.conv1_1 = nn.Conv2D(
+            in_channels, channels[0], kernel_size=3, stride=1, padding=1)
         self.bn1_1 = nn.BatchNorm2D(channels[0])
         self.relu1_1 = nn.ReLU()
 
-        self.conv1_2 = nn.Conv2D(channels[0], channels[1], kernel_size=3, stride=1, padding=1)
+        self.conv1_2 = nn.Conv2D(
+            channels[0], channels[1], kernel_size=3, stride=1, padding=1)
         self.bn1_2 = nn.BatchNorm2D(channels[1])
         self.relu1_2 = nn.ReLU()
 
         # conv 2 (Max-pooling, Residual block, Conv)
-        self.pool2 = nn.MaxPool2D(kernel_size=2, stride=2, padding=0, ceil_mode=True)
+        self.pool2 = nn.MaxPool2D(
+            kernel_size=2, stride=2, padding=0, ceil_mode=True)
         self.block2 = self._make_layer(channels[1], channels[2], layers[0])
-        self.conv2 = nn.Conv2D(channels[2], channels[2], kernel_size=3, stride=1, padding=1)
+        self.conv2 = nn.Conv2D(
+            channels[2], channels[2], kernel_size=3, stride=1, padding=1)
         self.bn2 = nn.BatchNorm2D(channels[2])
         self.relu2 = nn.ReLU()
 
         # conv 3 (Max-pooling, Residual block, Conv)
-        self.pool3 = nn.MaxPool2D(kernel_size=2, stride=2, padding=0, ceil_mode=True)
+        self.pool3 = nn.MaxPool2D(
+            kernel_size=2, stride=2, padding=0, ceil_mode=True)
         self.block3 = self._make_layer(channels[2], channels[3], layers[1])
-        self.conv3 = nn.Conv2D(channels[3], channels[3], kernel_size=3, stride=1, padding=1)
+        self.conv3 = nn.Conv2D(
+            channels[3], channels[3], kernel_size=3, stride=1, padding=1)
         self.bn3 = nn.BatchNorm2D(channels[3])
         self.relu3 = nn.ReLU()
 
         # conv 4 (Max-pooling, Residual block, Conv)
-        self.pool4 = nn.MaxPool2D(kernel_size=(2, 1), stride=(2, 1), padding=0, ceil_mode=True)
+        self.pool4 = nn.MaxPool2D(
+            kernel_size=(2, 1), stride=(2, 1), padding=0, ceil_mode=True)
         self.block4 = self._make_layer(channels[3], channels[4], layers[2])
-        self.conv4 = nn.Conv2D(channels[4], channels[4], kernel_size=3, stride=1, padding=1)
+        self.conv4 = nn.Conv2D(
+            channels[4], channels[4], kernel_size=3, stride=1, padding=1)
         self.bn4 = nn.BatchNorm2D(channels[4])
         self.relu4 = nn.ReLU()
 
         # conv 5 ((Max-pooling), Residual block, Conv)
         self.pool5 = None
         if self.last_stage_pool:
-            self.pool5 = nn.MaxPool2D(kernel_size=2, stride=2, padding=0, ceil_mode=True)
+            self.pool5 = nn.MaxPool2D(
+                kernel_size=2, stride=2, padding=0, ceil_mode=True)
         self.block5 = self._make_layer(channels[4], channels[5], layers[3])
-        self.conv5 = nn.Conv2D(channels[5], channels[5], kernel_size=3, stride=1, padding=1)
+        self.conv5 = nn.Conv2D(
+            channels[5], channels[5], kernel_size=3, stride=1, padding=1)
         self.bn5 = nn.BatchNorm2D(channels[5])
         self.relu5 = nn.ReLU()
 
         self.out_channels = channels[-1]
-    
+
     def _make_layer(self, input_channels, output_channels, blocks):
         layers = []
         for _ in range(blocks):
@@ -130,19 +164,19 @@ class ResNet31(nn.Layer):
             if input_channels != output_channels:
                 downsample = nn.Sequential(
                     nn.Conv2D(
-                        input_channels, 
-                        output_channels, 
-                        kernel_size=1, 
-                        stride=1, 
+                        input_channels,
+                        output_channels,
+                        kernel_size=1,
+                        stride=1,
                         bias_attr=False),
-                    nn.BatchNorm2D(output_channels),
-                )
-                
-            layers.append(BasicBlock(input_channels, output_channels, downsample=downsample))
+                    nn.BatchNorm2D(output_channels), )
+
+            layers.append(
+                BasicBlock(
+                    input_channels, output_channels, downsample=downsample))
             input_channels = output_channels
         return nn.Sequential(*layers)
 
-
     def forward(self, x):
         x = self.conv1_1(x)
         x = self.bn1_1(x)
@@ -166,11 +200,11 @@ class ResNet31(nn.Layer):
             x = block_layer(x)
             x = conv_layer(x)
             x = bn_layer(x)
-            x= relu_layer(x)
+            x = relu_layer(x)
 
             outs.append(x)
-        
+
         if self.out_indices is not None:
             return tuple([outs[i] for i in self.out_indices])
-        
+
         return x
diff --git a/ppocr/modeling/backbones/rec_resnet_aster.py b/ppocr/modeling/backbones/rec_resnet_aster.py
index bdecaf46af98f9b967d9a339f82d4e938abdc6d9..6a2710dfa079b4d910146c10ca2cff31321b2513 100644
--- a/ppocr/modeling/backbones/rec_resnet_aster.py
+++ b/ppocr/modeling/backbones/rec_resnet_aster.py
@@ -11,7 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+"""
+This code is refer from:
+https://github.com/ayumiymk/aster.pytorch/blob/master/lib/models/resnet_aster.py
+"""
 import paddle
 import paddle.nn as nn
 
diff --git a/ppocr/modeling/heads/det_pse_head.py b/ppocr/modeling/heads/det_pse_head.py
index db800f57a216ab437b724988ce692a9ac0c545d9..32a5b48e190b7566411b19841b6aa14455b5d41d 100644
--- a/ppocr/modeling/heads/det_pse_head.py
+++ b/ppocr/modeling/heads/det_pse_head.py
@@ -1,4 +1,4 @@
-# copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
+# copyright (c) 2021 PaddlePaddle Authors. All Rights Reserve.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -11,22 +11,24 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/whai362/PSENet/blob/python3/models/head/psenet_head.py
+"""
+
 from paddle import nn
 
 
 class PSEHead(nn.Layer):
-    def __init__(self,
-                 in_channels,
-                 hidden_dim=256,
-                 out_channels=7,
-                 **kwargs):
+    def __init__(self, in_channels, hidden_dim=256, out_channels=7, **kwargs):
         super(PSEHead, self).__init__()
-        self.conv1 = nn.Conv2D(in_channels, hidden_dim, kernel_size=3, stride=1, padding=1)
+        self.conv1 = nn.Conv2D(
+            in_channels, hidden_dim, kernel_size=3, stride=1, padding=1)
         self.bn1 = nn.BatchNorm2D(hidden_dim)
         self.relu1 = nn.ReLU()
 
-        self.conv2 = nn.Conv2D(hidden_dim, out_channels, kernel_size=1, stride=1, padding=0)
-
+        self.conv2 = nn.Conv2D(
+            hidden_dim, out_channels, kernel_size=1, stride=1, padding=0)
 
     def forward(self, x, **kwargs):
         out = self.conv1(x)
diff --git a/ppocr/modeling/heads/rec_aster_head.py b/ppocr/modeling/heads/rec_aster_head.py
index 4961897b409020fe6cff72eb96f3257156fa33ac..9240f002d3a8bcbde517142be6b45559430de610 100644
--- a/ppocr/modeling/heads/rec_aster_head.py
+++ b/ppocr/modeling/heads/rec_aster_head.py
@@ -11,6 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/ayumiymk/aster.pytorch/blob/master/lib/models/attention_recognition_head.py
+"""
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
diff --git a/ppocr/modeling/heads/rec_att_head.py b/ppocr/modeling/heads/rec_att_head.py
index 4286d7691d1abcf80c283d1c1ab76f8cd1f4a634..6d77e42eb5def579052687ab6fdc265159311884 100644
--- a/ppocr/modeling/heads/rec_att_head.py
+++ b/ppocr/modeling/heads/rec_att_head.py
@@ -75,7 +75,7 @@ class AttentionHead(nn.Layer):
                             probs_step, axis=1)], axis=1)
                 next_input = probs_step.argmax(axis=1)
                 targets = next_input
-
+            probs = paddle.nn.functional.softmax(probs, axis=2)
         return probs
 
 
diff --git a/ppocr/modeling/heads/rec_sar_head.py b/ppocr/modeling/heads/rec_sar_head.py
index 2f15801b7057001a8af92ec676ef49f5ac7a9f78..a46cce7de2c8e59cf797db96fc6fcb7e25fa549a 100644
--- a/ppocr/modeling/heads/rec_sar_head.py
+++ b/ppocr/modeling/heads/rec_sar_head.py
@@ -1,3 +1,22 @@
+# copyright (c) 2021 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+This code is refer from: 
+https://github.com/open-mmlab/mmocr/blob/main/mmocr/models/textrecog/encoders/sar_encoder.py
+https://github.com/open-mmlab/mmocr/blob/main/mmocr/models/textrecog/decoders/sar_decoder.py
+"""
+
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
diff --git a/ppocr/modeling/necks/fpn.py b/ppocr/modeling/necks/fpn.py
index 8728a5c9ded5b9c174fd34f088d8012961f65ec0..48c85b1e53bd889bc887e8fedcd33b1b12cb734b 100644
--- a/ppocr/modeling/necks/fpn.py
+++ b/ppocr/modeling/necks/fpn.py
@@ -11,64 +11,102 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/whai362/PSENet/blob/python3/models/neck/fpn.py
+"""
 
 import paddle.nn as nn
 import paddle
 import math
 import paddle.nn.functional as F
 
+
 class Conv_BN_ReLU(nn.Layer):
-    def __init__(self, in_planes, out_planes, kernel_size=1, stride=1, padding=0):
+    def __init__(self,
+                 in_planes,
+                 out_planes,
+                 kernel_size=1,
+                 stride=1,
+                 padding=0):
         super(Conv_BN_ReLU, self).__init__()
-        self.conv = nn.Conv2D(in_planes, out_planes, kernel_size=kernel_size, stride=stride, padding=padding,
-                              bias_attr=False)
+        self.conv = nn.Conv2D(
+            in_planes,
+            out_planes,
+            kernel_size=kernel_size,
+            stride=stride,
+            padding=padding,
+            bias_attr=False)
         self.bn = nn.BatchNorm2D(out_planes, momentum=0.1)
         self.relu = nn.ReLU()
 
         for m in self.sublayers():
             if isinstance(m, nn.Conv2D):
                 n = m._kernel_size[0] * m._kernel_size[1] * m._out_channels
-                m.weight = paddle.create_parameter(shape=m.weight.shape, dtype='float32', default_initializer=paddle.nn.initializer.Normal(0, math.sqrt(2. / n)))
+                m.weight = paddle.create_parameter(
+                    shape=m.weight.shape,
+                    dtype='float32',
+                    default_initializer=paddle.nn.initializer.Normal(
+                        0, math.sqrt(2. / n)))
             elif isinstance(m, nn.BatchNorm2D):
-                m.weight = paddle.create_parameter(shape=m.weight.shape, dtype='float32', default_initializer=paddle.nn.initializer.Constant(1.0))
-                m.bias = paddle.create_parameter(shape=m.bias.shape, dtype='float32', default_initializer=paddle.nn.initializer.Constant(0.0))
+                m.weight = paddle.create_parameter(
+                    shape=m.weight.shape,
+                    dtype='float32',
+                    default_initializer=paddle.nn.initializer.Constant(1.0))
+                m.bias = paddle.create_parameter(
+                    shape=m.bias.shape,
+                    dtype='float32',
+                    default_initializer=paddle.nn.initializer.Constant(0.0))
 
     def forward(self, x):
         return self.relu(self.bn(self.conv(x)))
 
+
 class FPN(nn.Layer):
     def __init__(self, in_channels, out_channels):
         super(FPN, self).__init__()
 
         # Top layer
-        self.toplayer_ = Conv_BN_ReLU(in_channels[3], out_channels, kernel_size=1, stride=1, padding=0)
+        self.toplayer_ = Conv_BN_ReLU(
+            in_channels[3], out_channels, kernel_size=1, stride=1, padding=0)
         # Lateral layers
-        self.latlayer1_ = Conv_BN_ReLU(in_channels[2], out_channels, kernel_size=1, stride=1, padding=0)
+        self.latlayer1_ = Conv_BN_ReLU(
+            in_channels[2], out_channels, kernel_size=1, stride=1, padding=0)
 
-        self.latlayer2_ = Conv_BN_ReLU(in_channels[1], out_channels, kernel_size=1, stride=1, padding=0)
+        self.latlayer2_ = Conv_BN_ReLU(
+            in_channels[1], out_channels, kernel_size=1, stride=1, padding=0)
 
-        self.latlayer3_ = Conv_BN_ReLU(in_channels[0], out_channels, kernel_size=1, stride=1, padding=0)
+        self.latlayer3_ = Conv_BN_ReLU(
+            in_channels[0], out_channels, kernel_size=1, stride=1, padding=0)
 
         # Smooth layers
-        self.smooth1_ = Conv_BN_ReLU(out_channels, out_channels, kernel_size=3, stride=1, padding=1)
-
-        self.smooth2_ = Conv_BN_ReLU(out_channels, out_channels, kernel_size=3, stride=1, padding=1)
+        self.smooth1_ = Conv_BN_ReLU(
+            out_channels, out_channels, kernel_size=3, stride=1, padding=1)
 
-        self.smooth3_ = Conv_BN_ReLU(out_channels, out_channels, kernel_size=3, stride=1, padding=1)
+        self.smooth2_ = Conv_BN_ReLU(
+            out_channels, out_channels, kernel_size=3, stride=1, padding=1)
 
+        self.smooth3_ = Conv_BN_ReLU(
+            out_channels, out_channels, kernel_size=3, stride=1, padding=1)
 
         self.out_channels = out_channels * 4
         for m in self.sublayers():
             if isinstance(m, nn.Conv2D):
                 n = m._kernel_size[0] * m._kernel_size[1] * m._out_channels
-                m.weight = paddle.create_parameter(shape=m.weight.shape, dtype='float32',
-                                                   default_initializer=paddle.nn.initializer.Normal(0,
-                                                                                                    math.sqrt(2. / n)))
+                m.weight = paddle.create_parameter(
+                    shape=m.weight.shape,
+                    dtype='float32',
+                    default_initializer=paddle.nn.initializer.Normal(
+                        0, math.sqrt(2. / n)))
             elif isinstance(m, nn.BatchNorm2D):
-                m.weight = paddle.create_parameter(shape=m.weight.shape, dtype='float32',
-                                                   default_initializer=paddle.nn.initializer.Constant(1.0))
-                m.bias = paddle.create_parameter(shape=m.bias.shape, dtype='float32',
-                                                 default_initializer=paddle.nn.initializer.Constant(0.0))
+                m.weight = paddle.create_parameter(
+                    shape=m.weight.shape,
+                    dtype='float32',
+                    default_initializer=paddle.nn.initializer.Constant(1.0))
+                m.bias = paddle.create_parameter(
+                    shape=m.bias.shape,
+                    dtype='float32',
+                    default_initializer=paddle.nn.initializer.Constant(0.0))
 
     def _upsample(self, x, scale=1):
         return F.upsample(x, scale_factor=scale, mode='bilinear')
@@ -81,15 +119,15 @@ class FPN(nn.Layer):
         p5 = self.toplayer_(f5)
 
         f4 = self.latlayer1_(f4)
-        p4 = self._upsample_add(p5, f4,2)
+        p4 = self._upsample_add(p5, f4, 2)
         p4 = self.smooth1_(p4)
 
         f3 = self.latlayer2_(f3)
-        p3 = self._upsample_add(p4, f3,2)
+        p3 = self._upsample_add(p4, f3, 2)
         p3 = self.smooth2_(p3)
 
         f2 = self.latlayer3_(f2)
-        p2 = self._upsample_add(p3, f2,2)
+        p2 = self._upsample_add(p3, f2, 2)
         p2 = self.smooth3_(p2)
 
         p3 = self._upsample(p3, 2)
@@ -97,4 +135,4 @@ class FPN(nn.Layer):
         p5 = self._upsample(p5, 8)
 
         fuse = paddle.concat([p2, p3, p4, p5], axis=1)
-        return fuse
\ No newline at end of file
+        return fuse
diff --git a/ppocr/modeling/transforms/stn.py b/ppocr/modeling/transforms/stn.py
index 215895f4c4c719f407f4998f7429d965e0529ddc..6f2bdda050f217d8253740001901fbff4065782a 100644
--- a/ppocr/modeling/transforms/stn.py
+++ b/ppocr/modeling/transforms/stn.py
@@ -11,7 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+"""
+This code is refer from:
+https://github.com/ayumiymk/aster.pytorch/blob/master/lib/models/stn_head.py
+"""
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
diff --git a/ppocr/modeling/transforms/tps.py b/ppocr/modeling/transforms/tps.py
index 6cd68555369dd1ddbd6ccf5236688a4b957b8525..9bdab0f85112b90d8da959dce4e258188a812052 100644
--- a/ppocr/modeling/transforms/tps.py
+++ b/ppocr/modeling/transforms/tps.py
@@ -11,6 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/clovaai/deep-text-recognition-benchmark/blob/master/modules/transformation.py
+"""
 
 from __future__ import absolute_import
 from __future__ import division
diff --git a/ppocr/modeling/transforms/tps_spatial_transformer.py b/ppocr/modeling/transforms/tps_spatial_transformer.py
index b510acb0d4012c9a4d90c7ca07cac895f0bf242e..4db34f7b4833c1c9b2901c68899bfb294b5843c4 100644
--- a/ppocr/modeling/transforms/tps_spatial_transformer.py
+++ b/ppocr/modeling/transforms/tps_spatial_transformer.py
@@ -11,6 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/ayumiymk/aster.pytorch/blob/master/lib/models/tps_spatial_transformer.py
+"""
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
diff --git a/ppocr/postprocess/locality_aware_nms.py b/ppocr/postprocess/locality_aware_nms.py
index 53280cc13ed7e41859e23e2517938d4f6eb07076..d305ef681882b4a393a73190bcbd20a65d1f0c15 100644
--- a/ppocr/postprocess/locality_aware_nms.py
+++ b/ppocr/postprocess/locality_aware_nms.py
@@ -1,5 +1,6 @@
 """
 Locality aware nms.
+This code is refered from: https://github.com/songdejia/EAST/blob/master/locality_aware_nms.py
 """
 
 import numpy as np
diff --git a/ppocr/postprocess/pse_postprocess/pse/README.md b/ppocr/postprocess/pse_postprocess/pse/README.md
index 9c2d9eaeaa5f93550358ebdd4d9161330b78a86f..6a19d5d1b6b1d8e6952eb054d74c6672ed10bc48 100644
--- a/ppocr/postprocess/pse_postprocess/pse/README.md
+++ b/ppocr/postprocess/pse_postprocess/pse/README.md
@@ -1,5 +1,6 @@
 ## 编译
-code from https://github.com/whai362/pan_pp.pytorch
+This code is refer from:
+https://github.com/whai362/PSENet/blob/python3/models/post_processing/pse
 ```python
 python3 setup.py build_ext --inplace
 ```
diff --git a/ppocr/postprocess/pse_postprocess/pse_postprocess.py b/ppocr/postprocess/pse_postprocess/pse_postprocess.py
index 4b89d221d284602933ab3d4f21468fcae79ef310..0234d592d6dde8419b1d623e33b9ca5bb251fb97 100755
--- a/ppocr/postprocess/pse_postprocess/pse_postprocess.py
+++ b/ppocr/postprocess/pse_postprocess/pse_postprocess.py
@@ -1,16 +1,20 @@
-# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
+# copyright (c) 2021 PaddlePaddle Authors. All Rights Reserve.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
-#     http://www.apache.org/licenses/LICENSE-2.0
+#    http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/whai362/PSENet/blob/python3/models/head/psenet_head.py
+"""
 
 from __future__ import absolute_import
 from __future__ import division
@@ -47,7 +51,8 @@ class PSEPostProcess(object):
         pred = outs_dict['maps']
         if not isinstance(pred, paddle.Tensor):
             pred = paddle.to_tensor(pred)
-        pred = F.interpolate(pred, scale_factor=4 // self.scale, mode='bilinear')
+        pred = F.interpolate(
+            pred, scale_factor=4 // self.scale, mode='bilinear')
 
         score = F.sigmoid(pred[:, 0, :, :])
 
@@ -60,7 +65,9 @@ class PSEPostProcess(object):
 
         boxes_batch = []
         for batch_index in range(pred.shape[0]):
-            boxes, scores = self.boxes_from_bitmap(score[batch_index], kernels[batch_index], shape_list[batch_index])
+            boxes, scores = self.boxes_from_bitmap(score[batch_index],
+                                                   kernels[batch_index],
+                                                   shape_list[batch_index])
 
             boxes_batch.append({'points': boxes, 'scores': scores})
         return boxes_batch
@@ -98,15 +105,14 @@ class PSEPostProcess(object):
                 mask = np.zeros((box_height, box_width), np.uint8)
                 mask[points[:, 1], points[:, 0]] = 255
 
-                contours, _ = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
+                contours, _ = cv2.findContours(mask, cv2.RETR_EXTERNAL,
+                                               cv2.CHAIN_APPROX_SIMPLE)
                 bbox = np.squeeze(contours[0], 1)
             else:
                 raise NotImplementedError
 
-            bbox[:, 0] = np.clip(
-                np.round(bbox[:, 0] / ratio_w), 0, src_w)
-            bbox[:, 1] = np.clip(
-                np.round(bbox[:, 1] / ratio_h), 0, src_h)
+            bbox[:, 0] = np.clip(np.round(bbox[:, 0] / ratio_w), 0, src_w)
+            bbox[:, 1] = np.clip(np.round(bbox[:, 1] / ratio_h), 0, src_h)
             boxes.append(bbox)
             scores.append(score_i)
         return boxes, scores
diff --git a/ppocr/utils/iou.py b/ppocr/utils/iou.py
index 20529dee2d14083f3de4ac034668d004136c56e2..35459f5f053cde0a74f76c5652bfb723a48ca890 100644
--- a/ppocr/utils/iou.py
+++ b/ppocr/utils/iou.py
@@ -1,4 +1,4 @@
-# copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
+# copyright (c) 2021 PaddlePaddle Authors. All Rights Reserve.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -11,18 +11,23 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/whai362/PSENet/blob/python3/models/loss/iou.py
+"""
 
 import paddle
 
 EPS = 1e-6
 
+
 def iou_single(a, b, mask, n_class):
     valid = mask == 1
     a = a.masked_select(valid)
     b = b.masked_select(valid)
     miou = []
     for i in range(n_class):
-        if a.shape == [0] and a.shape==b.shape:
+        if a.shape == [0] and a.shape == b.shape:
             inter = paddle.to_tensor(0.0)
             union = paddle.to_tensor(0.0)
         else:
@@ -32,6 +37,7 @@ def iou_single(a, b, mask, n_class):
     miou = sum(miou) / len(miou)
     return miou
 
+
 def iou(a, b, mask, n_class=2, reduce=True):
     batch_size = a.shape[0]
 
@@ -39,10 +45,10 @@ def iou(a, b, mask, n_class=2, reduce=True):
     b = b.reshape([batch_size, -1])
     mask = mask.reshape([batch_size, -1])
 
-    iou = paddle.zeros((batch_size,), dtype='float32')
+    iou = paddle.zeros((batch_size, ), dtype='float32')
     for i in range(batch_size):
         iou[i] = iou_single(a[i], b[i], mask[i], n_class)
 
     if reduce:
         iou = paddle.mean(iou)
-    return iou
\ No newline at end of file
+    return iou
diff --git a/ppocr/utils/logging.py b/ppocr/utils/logging.py
index 11896c37d9285e19a9526caa9c637d7eda7b1979..ce827e8b10c4b63b736886a2f72106c7570576b1 100644
--- a/ppocr/utils/logging.py
+++ b/ppocr/utils/logging.py
@@ -1,4 +1,4 @@
-# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
+# copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -11,6 +11,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+"""
+This code is refer from:
+https://github.com/WenmuZhou/PytorchOCR/blob/master/torchocr/utils/logging.py
+"""
 
 import os
 import sys