fn main() {
    #[derive(Debug)]
    enum Foo {
        Bar,
        Boo { a: usize },
    }

    impl Foo {
        fn print(&self) {
            println!("{:?}", self);
        }

        fn boo(a: usize) -> Self {
            Foo::Boo { a }
        }

        fn bar() -> Self {
            Foo::Bar
        }
    }

    Foo::boo(123).print();
    Foo::bar().print();
}