fix testcases on Python 3.x
diff --git a/example/example16.py b/example/example16.py
index 82102ea..b4bcb65 100644
--- a/example/example16.py
+++ b/example/example16.py
@@ -7,6 +7,6 @@
 from example import return_class_2
 from example import return_none
 
-print(type(return_class_1()))
-print(type(return_class_2()))
-print(type(return_none()))
+print(type(return_class_1()).__name__)
+print(type(return_class_2()).__name__)
+print(type(return_none()).__name__)