You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: traits.rs
    path of file: ./repos/tao-of-rust-codes/src/ch03
    
    the code of the file until where you have to start completion: /// # trait: 关联类型
///
/// Base usage:
///
/// ```
/// pub fn associated_type(){
///     #[derive(Debug, Parti
    
pub fn trait_bound(){
    use std::ops::Add;
    fn sum<T: Add<T, Output=T>>(a: T, b: T) -> T{
        a + b
    }
    assert_eq!(sum(1u32, 2u32), 3);
    assert_eq!(sum(1u64, 2u64), 3);
}