from collections import deque

class Shape:

    def __init__(self, name: str):
        self.name = name

    def describe(self) -> str:
        return f'shape<{self.name}>'

    def area(self) -> float:
        raise NotImplementedError

class Rect(Shape):

    def __init__(self, w: float, h: float):
        super().__init__('rect')
        self.w = w
        self.h = h

    def area(self) -> float:
        return self.w * self.h

class Circle(Shape):

    def __init__(self, r: float):
        super().__init__('circle')
        self.r = r

    def area(self) -> float:
        return 3.14159265 * self.r * self.r

def total_area(shapes):
    q = deque(shapes)
    total = 0.0
    while q:
        s = q.popleft()
        try:
            total += s.area()
        except NotImplementedError:
            continue
    return total
if __name__ == '__main__':
    shapes = [Rect(3, 4), Circle(5), Rect(1, 1), Circle(2)]
    for s in shapes:
        print(s.describe(), '->', round(s.area(), 4))
    print('total area:', round(total_area(shapes), 4))