class A(object):
    def do_nothing(self):
        return self

    def fail(self, t=None):
        raise RuntimeError('fail')


def main():
    a = A()

    (a
        .do_nothing()
        .do_nothing()
        .fail()
        .fail()
        .do_nothing()
    )


if __name__ == '__main__':
    main()