Macro expecto_patronum 

macro_rules! expecto_patronum {
    ($danger:expr, $message:expr) => { ... };
    ($danger:expr) => { ... };
}

Appends .expect(message) if given a message, otherwise appends .unwrap().

Examples

expecto_patronum!(u8::try_from(5));

expecto_patronum!(u8::try_from(-5), "Here be Dementors!");