example code

content/refactoring/as-class.py

@@ -0,0 +1,21 @@
+import math
+
+
+class Moon:
+    def __init__(self, name, radius, contains_water=False):
+        self.name = name
+        self.radius = radius  # in kilometers
+        self.contains_water = contains_water
+
+    def surface_area(self) -> float:
+        """Calculate the surface area of the moon assuming a spherical shape."""
+        return 4.0 * math.pi * self.radius**2
+
+    def __repr__(self):
+        return f"Moon(name={self.name!r}, radius={self.radius}, contains_water={self.contains_water})"
+
+
+europa = Moon(name="Europa", radius=1560.8, contains_water=True)
+
+print(europa)
+print(f"Surface area (km^2) of {europa.name}: {europa.surface_area()}")

content/refactoring/as-dataclass.py

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+from dataclasses import dataclass
+import math
+
+
+@dataclass
+class Moon:
+    name: str
+    radius: float  # in kilometers
+    contains_water: bool = False
+
+    def surface_area(self) -> float:
+        """Calculate the surface area of the moon assuming a spherical shape."""
+        return 4.0 * math.pi * self.radius**2
+
+
+europa = Moon(name="Europa", radius=1560.8, contains_water=True)
+
+print(europa)
+print(f"Surface area (km^2) of {europa.name}: {europa.surface_area()}")

content/refactoring/using-dict.py

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+import math
+
+
+def surface_area(radius: float) -> float:
+    return 4.0 * math.pi * radius**2
+
+
+europa = {"name": "Europa", "radius": 1560.8, "contains_water": True}
+
+
+print(europa)
+print(f"Surface area (km^2) of {europa['name']}: {surface_area(europa['radius'])}")