diff --git a/src/jsonrpc/extractor.py b/src/jsonrpc/extractor.py
index 927efc5..26d8904 100644
--- a/src/jsonrpc/extractor.py
+++ b/src/jsonrpc/extractor.py
@@ -5,7 +5,7 @@ from .exceptions import InvalidParamsError
 
 
 def Extract(handler):
-    wrapper(query):
+    def wrapper(query):
         params = None
         if 'params' in query:
             params = query['params']