diff --git a/lms/envs/devstack.py b/lms/envs/devstack.py
index 501534cdc4..00cb4b3596 100644
--- a/lms/envs/devstack.py
+++ b/lms/envs/devstack.py
@@ -49,7 +49,7 @@ DEBUG_TOOLBAR_PANELS = (
 
 DEBUG_TOOLBAR_CONFIG = {
     'INTERCEPT_REDIRECTS': False,
-    'SHOW_TOOLBAR_CALLBACK': lambda: True,
+    'SHOW_TOOLBAR_CALLBACK': lambda _: True,
 }
 
 ########################### PIPELINE #################################