diff --git a/Parser/asdl.py b/Parser/asdl.py
index 8fbd9ec9fe1..71d3be7f8a5 100644
--- a/Parser/asdl.py
+++ b/Parser/asdl.py
@@ -181,7 +181,7 @@ def p_sum_0(self, constructor):
         " sum ::= constructor """
         return [constructor[0]]
 
-    def p_sum_1(self, ):
+    def p_sum_1(self, info):
         " sum ::= constructor | sum "
         constructor, _, sum = info
         return [constructor] + sum