diff --git a/tests/CleanScreen.py b/tests/CleanScreen.py
new file mode 100644
index 0000000..80714ef
--- /dev/null
+++ b/tests/CleanScreen.py
@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+
+# import only system from os
+from os import system, name
+
+# import sleep to show output for some time period
+from time import sleep
+
+
+# define our clear function
+def clear():
+    # for windows
+    if name == 'nt':
+        _ = system('cls')
+
+    # for mac and linux(here, os.name is 'posix')
+    else:
+        _ = system('clear')
+
+    # print out some text
+
+
+print('Hello CWIKIUS\n' * 10)
+
+# sleep for 2 seconds after printing output
+sleep(2)
+
+# now call function we defined above
+clear()
diff --git a/tests/Variables.py b/tests/Variables.py
index 5384a49..c5f830e 100644
--- a/tests/Variables.py
+++ b/tests/Variables.py
@@ -24,9 +24,11 @@ print(x)
 print(y)
 
 # 类型转换
-x = str(3)  # x will be '3'
-y = int(3)  # y will be 3
-z = float(3)  # z will be 3.0
+x1 = str(3)  # x will be '3'
+x2 = int(3)  # y will be 3
+x3 = float(3)  # z will be 3.0
+x4 = chr(31243)  # z will be 3.0
+x5 = ord('程')  # z will be 3.0
 
 # 获得类型
 print("==================")