diff --git a/README.md b/README.md
index 557cf2b..3b01d90 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,10 @@ Chinese Synonyms for Natural Language Processing and Understanding.
 
 ```synonyms```可以用于自然语言理解的很多任务：文本对齐，推荐算法，相似度计算，语义偏移，关键字提取，概念提取，自动摘要，搜索引擎等。
 
-![](https://camo.githubusercontent.com/ae91a5698ad80d3fe8e0eb5a4c6ee7170e088a7d/687474703a2f2f37786b6571692e636f6d312e7a302e676c622e636c6f7564646e2e636f6d2f61692f53637265656e25323053686f74253230323031372d30342d30342532306174253230382e32302e3437253230504d2e706e67)
+[![chatoper banner][co-banner-image]][co-url]
+
+[co-banner-image]: https://user-images.githubusercontent.com/3538629/42217321-3d5e44f6-7ef7-11e8-94e7-1574bfa1dbb8.png
+[co-url]: https://www.chatopera.com
 
 # Table of Content:
 
diff --git a/demo.py b/demo.py
index 161fd64..dbfd7ca 100755
--- a/demo.py
+++ b/demo.py
@@ -128,6 +128,9 @@ class Test(unittest.TestCase):
         synonyms.display("北新桥")  # synonyms.display calls synonyms.nearby
 
 
+    def test_badcase_1(self):
+        synonyms.display("人脸")  # synonyms.display calls synonyms.nearby
+
 def test():
     unittest.main()