Implementation of object authenticity judgment condition using __bool__ method

reserve_bool.py

import math

class Coordinate:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __bool__(self):
        print('__bool__')
        return self.x != 0 or self.y != 0
    def __len__(self):
        print('__len__')
        return int(math.sqrt(self.x **2 + self.y **2))

if __name__ == '__main__':
    c = Coordinate(0,0)
    if c:
        print('c is True.')
    else:
        print('c is False.')

Self-study python Quoted from Chapter 11 Object-Oriented Syntax