Added a new example to Calculator-App.md

Author: kana800

Projects/1-Beginner/Calculator-App.md

@@ -56,3 +56,4 @@ number.
 - [Javascript Calculator](https://codepen.io/giana/pen/GJMBEv)
 - [React Calculator](https://codepen.io/mjijackson/pen/xOzyGX)
 - [Javascript-CALC](https://github.com/x0uter/javascript-calc)
+- [Python Calculator](https://github.com/kana800/Side-Projects/tree/master/1-Beginner/calculator)