Drill 24: Improve it — Methods and interfaces

package main

import "fmt"

type Notifier interface {
    Notify() string
}

type Lesson struct {
    Title   string
    minutes int
}

func (l Lesson) Notify() string {
    return "Lesson: " + l.Title
}

func (l *Lesson) Complete() {
    l.minutes = 0
}

func announce(n Notifier) {
    fmt.Println(n.Notify())
}

func main() {
    lesson := Lesson{Title: "Methods and interfaces", minutes: 14}
    announce(lesson)
    lesson.Complete()
    fmt.Println(lesson.minutes)
}