feat: robotpy is a tutorial for polymorphism

src/tutorial/class/robot.py

@@ -0,0 +1,21 @@
+class Dog:
+    def speak(self) -> str:
+        return "wuff"
+
+
+class Cat:
+    def speak(self) -> str:
+        return "miau"
+
+
+class Robot:
+    def speak(self) -> str:
+        return "bip bup"
+
+
+def chorus(animals) -> list:
+    for a in animals:
+        print(a.speak())
+
+
+chorus([Dog(), Cat(), Robot()])