diff --git a/Parser/asdl.py b/Parser/asdl.py
index a3701e6..8fbd9ec 100644
--- a/Parser/asdl.py
+++ b/Parser/asdl.py
@@ -103,7 +103,7 @@
 
     def t_default(self, s):
         r" . +"
-        raise ValueError, "unmatched input: %r" % s
+        raise ValueError("unmatched input: %r" % s)
 
 class ASDLParser(spark.GenericParser, object):
     def __init__(self):