Trait with inherent implementation

traitimpl.rs

struct Person {
    name: String, // NB there's a comma here 
    surname: String, 
    age: u32
}

// notice now we are defining impl METHOD for TYPE
impl WhoAreYou for Person {
  fn who_are_you(&self) -> String{
      return format!("Person name is {} surname {} and age {}", self.name, self.surname, self.age);
  }
}