diff --git a/requirements_dev.txt b/requirements_dev.txt
index f0486d78d9de949b1735de6fbf7c3f402fc48fff..f0aae6fbd5ed0d64bb4beaf287a8a4c413d60b4e 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -19,7 +19,6 @@ importlib-resources>=1.0.1
 six>=1.12.0
 timeout-decorator>=0.4.1
 attrs
-ushlex
 gym==0.14.0
 flask
 flask_cors