diff --git a/manticore/ethereum.py b/manticore/ethereum.py
index 633fb2e..2ddbf9c 100644
--- a/manticore/ethereum.py
+++ b/manticore/ethereum.py
@@ -445,7 +445,7 @@ class EVMAccount(object):
     def address(self):
         return self._address
 
-    def _null_func():
+    def _null_func(self):
         pass