diff --git a/docs/quick_experience/python_use_hub.md b/docs/quick_experience/python_use_hub.md
index 1101e3f96297329ef2a6e15b7548a504c9a9b9cf..35d70802a1c34e0ccec84f940ce321afb97f5c1a 100644
--- a/docs/quick_experience/python_use_hub.md
+++ b/docs/quick_experience/python_use_hub.md
@@ -294,4 +294,3 @@ print("情感分析结果：", res)
 
 ## 总结
 PaddleHub提供了丰富的预训练模型，包括图像分类、语义模型、视频分类、图像生成、图像分割、文本审核、关键点检测等主流模型，只需要3行Python代码即可快速调用，即时输出预测结果，非常方便。您可以尝试一下，从[预训练模型列表](https://www.paddlepaddle.org.cn/hublist)中选择一些模型体验一下。
-
diff --git a/docs/tutorial/how_to_finetune.md b/docs/tutorial/how_to_finetune.md
index f14dce53f12dabd23d94e0caf8e423fd7609ea6a..d3e5a38a67d5e35e4eed074dad1bd2bd58d3d8d2 100644
--- a/docs/tutorial/how_to_finetune.md
+++ b/docs/tutorial/how_to_finetune.md
@@ -374,5 +374,3 @@ for batch_result in results:
 交通方便；环境很好；服务态度很好 房间较小	predict=1
 19天硬盘就罢工了，算上运来的一周都没用上15天，可就是不能换了。唉，你说这算什么事呀！	predict=0
 ```
-
-
diff --git a/docs/tutorial/how_to_load_data.md b/docs/tutorial/how_to_load_data.md
index 73e3ae8a068429a9b37fd1efd709bdace1509c32..b11065807da2175f557e755f3ddb6ca3108aef8f 100644
--- a/docs/tutorial/how_to_load_data.md
+++ b/docs/tutorial/how_to_load_data.md
@@ -71,4 +71,3 @@ label_list.txt内容如下：
 cat
 dog
 ```
-
diff --git a/paddlehub/commands/convert.py b/paddlehub/commands/convert.py
index 6fed432a4eb501673f8c39c004326b47485bb333..0ff13888c1b1105f893122a230bf093678483599 100644
--- a/paddlehub/commands/convert.py
+++ b/paddlehub/commands/convert.py
@@ -43,10 +43,8 @@ class ConvertCommand(BaseCommand):
             add_help=True)
         self.parser.add_argument('command')
         self.parser.add_argument('--module_name', '-n')
-        self.parser.add_argument('--module_version',
-                                 '-v',
-                                 nargs='?',
-                                 default='1.0.0')
+        self.parser.add_argument(
+            '--module_version', '-v', nargs='?', default='1.0.0')
         self.parser.add_argument('--model_dir', '-d')
         self.parser.add_argument('--output_dir', '-o')
 
@@ -62,27 +60,28 @@ class ConvertCommand(BaseCommand):
                     arcname = os.path.join(self.module, 'assets', file)
                     tfp.add(fullpath, arcname=arcname)
 
-            tfp.add(self.model_file,
-                    arcname=os.path.join(self.module, MODULE_FILE))
-            tfp.add(self.serving_file,
-                    arcname=os.path.join(self.module, SERVING_FILE))
-            tfp.add(self.init_file,
-                    arcname=os.path.join(self.module, INIT_FILE))
+            tfp.add(
+                self.model_file, arcname=os.path.join(self.module, MODULE_FILE))
+            tfp.add(
+                self.serving_file,
+                arcname=os.path.join(self.module, SERVING_FILE))
+            tfp.add(
+                self.init_file, arcname=os.path.join(self.module, INIT_FILE))
 
     def create_module_py(self):
-        template_file = open(os.path.join(TMPL_DIR, 'x_model.tmpl'),
-                             'r',
-                             encoding='utf-8')
+        template_file = open(
+            os.path.join(TMPL_DIR, 'x_model.tmpl'), 'r', encoding='utf-8')
         tmpl = Template(template_file.read())
         lines = []
 
         lines.append(
-            tmpl.substitute(NAME="'{}'".format(self.module),
-                            TYPE="'CV'",
-                            AUTHOR="'Baidu'",
-                            SUMMARY="''",
-                            VERSION="'{}'".format(self.version),
-                            EMAIL="''"))
+            tmpl.substitute(
+                NAME="'{}'".format(self.module),
+                TYPE="'CV'",
+                AUTHOR="'Baidu'",
+                SUMMARY="''",
+                VERSION="'{}'".format(self.version),
+                EMAIL="''"))
         # self.model_file = os.path.join(self.dest, MODULE_FILE)
         self.model_file = os.path.join(self._tmp_dir, MODULE_FILE)
         if os.path.exists(self.model_file):
@@ -101,9 +100,8 @@ class ConvertCommand(BaseCommand):
         shutil.copyfile(os.path.join(TMPL_DIR, 'init_py.tmpl'), self.init_file)
 
     def create_serving_demo_py(self):
-        template_file = open(os.path.join(TMPL_DIR, 'serving_demo.tmpl'),
-                             'r',
-                             encoding='utf-8')
+        template_file = open(
+            os.path.join(TMPL_DIR, 'serving_demo.tmpl'), 'r', encoding='utf-8')
         tmpl = Template(template_file.read())
         lines = []
 
diff --git a/paddlehub/tokenizer/tokenizer.py b/paddlehub/tokenizer/tokenizer.py
index f2f9111a1fbd974cb6ac1801a604d766228f29b0..3653cfd5d5ae5e645e7e78ae238bb9c5a730761d 100644
--- a/paddlehub/tokenizer/tokenizer.py
+++ b/paddlehub/tokenizer/tokenizer.py
@@ -78,11 +78,7 @@ class CustomTokenizer(object):
 
     def _convert_token_to_id(self, token):
         """ Converts a token (str) in an id using the vocab. """
-        v = self.vocab.get(token, None)
-        if v:
-            return v
-        else:
-            return 0
+        return self.vocab.get(token, None)
 
     def _convert_id_to_token(self, index):
         """Converts an index (integer) in a token (str) using the vocab."""
@@ -211,11 +207,11 @@ class CustomTokenizer(object):
                 return ids
             elif isinstance(text,
                             (list, tuple)) and len(text) > 0 and isinstance(
-                text[0], str):
+                                text[0], str):
                 return self.convert_tokens_to_ids(text)
             elif isinstance(text,
                             (list, tuple)) and len(text) > 0 and isinstance(
-                text[0], int):
+                                text[0], int):
                 return text
             else:
                 raise ValueError(
@@ -354,7 +350,7 @@ class CustomTokenizer(object):
         """
         out_string = (out_string.replace(" .", ".").replace(" ?", "?").replace(
             " !", "!").replace(" ,", ",").replace(" ' ", "'").replace(
-            " n't",
-            "n't").replace(" 'm", "'m").replace(" 's", "'s").replace(
-            " 've", "'ve").replace(" 're", "'re"))
+                " n't",
+                "n't").replace(" 'm", "'m").replace(" 's", "'s").replace(
+                    " 've", "'ve").replace(" 're", "'re"))
         return out_string
diff --git a/requirements.txt b/requirements.txt
index 967b6b0ab62b66865c4794bec68de9e959371709..a6c8bc55b9c7be6101cbf4f1ecc76c44d2f444fe 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,9 +10,10 @@ sentencepiece
 colorlog
 tqdm
 nltk
+opencv-python
 
 # pandas no longer support python2 in version 0.25 and above
-pandas ; python_version >= "3"
+pandas
 
 # gunicorn not support windows
 gunicorn >= 19.10.0; sys_platform != "win32"