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main.py

class Shape:
    def area(self) -> float:
        return 1.0

class Circle(Shape):
    def radius(self) -> float:
        return 2.0

# T is constrained to be Shape or a subclass of Shape
def total_area[T: Shape](shapes: tuple[T, ...]) -> float:
    return sum(s.area() for s in shapes)
    
total_area(shapes=(Shape(),Circle()))