Method count

Source Code/19-29.rs:24–32

(&self, key: u32)

            None
        }
        fn count(&self, key: u32) -> usize {
            let mut c = 0;
            for record in self.data.iter() {
                if record.id == key {
                    c += 1;
                }
            }
            c
        }
    }
    fn get_name<D>(dict: &D, id: u32) -> Option<String>
    where