from concurrent.futures import ProcessPoolExecutor, as_completed

class Foo:
    def __init__(self):
        self.spam = 'eggs'

    def bar(self):
        self.spam = 42
        print('4242')

    def doge(self):
        print(self.spam)

        with ProcessPoolExecutor(2) as pool:
            futures = [pool.submit(self.bar) for i in range(3)]
            for future in as_completed(futures):
                pass

        print(self.spam)


if __name__ == '__main__':
    wow = Foo()
    wow.doge()