diff --git a/apphelpers/utilities/types.py b/apphelpers/utilities/types.py
index 8b74ff5..c9a00ca 100644
--- a/apphelpers/utilities/types.py
+++ b/apphelpers/utilities/types.py
@@ -5,4 +5,4 @@
 
 
 def is_optional(t) -> bool:
-    return len(getattr(t, "__args__", [])) == 2 and t.__args__[1] == NoneType
+    return NoneType in getattr(t, "__args__", ())