diff --git a/class_person.py b/class_person.py
index be80e97..8fda2a6 100755
--- a/class_person.py
+++ b/class_person.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 
 class Person():
-    def __init__(self, name, age):
+    def __init__(self, *, name, age):
         self.name = name
         self.age = age
 
@@ -10,9 +10,9 @@ class Person():
 
 
 people = [
-    Person("tom", 22),
-    Person("jack", 11),
-    Person("jerry", 33)
+    Person(name="tom", age=22),
+    Person(name="jack", age=11),
+    Person(name="jerry", age=33),
 ]
 
 if __name__ == "__main__":
diff --git a/none_test.py b/none_test.py
index 6495760..31e9876 100644
--- a/none_test.py
+++ b/none_test.py
@@ -1,10 +1,10 @@
 #!/usr/bin/env python3
 
 if __name__ == "__main__":
-    b = None
+    b: None | bool = None
     print(b, ',', b is None, ',', b is not None, ',', b or False)
     b = True
     print(b, ',', b is None, ',', b is not None, ',', b or False)
 
-    s: str = None
+    s: None | str = None
     print(s, ',', s is None, ',', s or "value::test")