diff --git a/common/lib/capa/capa/responsetypes.py b/common/lib/capa/capa/responsetypes.py
index d5b0c86ec1..e18c894452 100644
--- a/common/lib/capa/capa/responsetypes.py
+++ b/common/lib/capa/capa/responsetypes.py
@@ -1911,7 +1911,7 @@ class OpenEndedResponse(LoncapaResponse):
 
         # Submit request. When successful, 'msg' is the prior length of the queue
         contents.update({'student_response': submission})
-        contents.update({'grader_type'} : self.grader_type)
+        contents.update({'grader_type' : self.grader_type})
         (error, msg) = qinterface.send_to_queue(header=xheader,
             body=json.dumps(contents))