Python class property

main.py

import math

class Test:

    def __init__(self):
        self.radius  = 0

    @property
    def perimeter(self):
        return self.radius 
    
    @perimeter.setter
    def perimeter(self, radius):
        if not isinstance(radius, int):
            raise Exception('Check the input')
        self.radius = 2 * math.pi * radius
        
def main():
    test = Test()
    test.perimeter = 1
    print(test.perimeter)

if __name__ == '__main__':
    main()