iface fooer {                                                                   
        fn foo() -> string;                                                     
}                                                                               
                                                                                
class foo {                                                                     
        fn foo() -> string {                                                    
                "Hello World"                                                   
        }                                                                       
        new() {}                                                                
}                                                                               
                                                                                
fn main() {                                                                     
        let g: fooer = foo::new();                                              
        println!(g.foo());                                                      
}