diff --git a/tests/functional/pyocf/rio.py b/tests/functional/pyocf/rio.py
index e857e02..09ef495 100644
--- a/tests/functional/pyocf/rio.py
+++ b/tests/functional/pyocf/rio.py
@@ -106,7 +106,6 @@ class Rio:
             return False
 
         def get_io_cb(self):
-            @CFUNCTYPE(c_void_p, c_int)
             def cb(error):
                 if error != 0:
                     self.errors.append(error)