use serde_derive::{Serialize, Deserialize}; // 1.0.94

#[derive(Deserialize, Serialize, Debug)]
pub struct CourseResult {
    pub key: String,
}


pub fn mapper(src: &Iterator<Item = &CourseResult>)  {

    src.map(|c| {
        println!("OK");
    });

}

fn main() {
    println!("hello");

}