diff --git a/lms/djangoapps/django_comment_client/tests/mock_cs_server/mock_cs_server.py b/lms/djangoapps/django_comment_client/tests/mock_cs_server/mock_cs_server.py
index ec5e6ea383..367485effb 100644
--- a/lms/djangoapps/django_comment_client/tests/mock_cs_server/mock_cs_server.py
+++ b/lms/djangoapps/django_comment_client/tests/mock_cs_server/mock_cs_server.py
@@ -45,7 +45,7 @@ class MockCommentServiceRequestHandler(BaseHTTPRequestHandler):
             self.end_headers()
             return False
 
-    def do_PUT self):
+    def do_PUT(self):
         '''
         Handle a PUT request from the client
         Used by the APIs for comment threads, commentables, comments,