Laravel：创建一个作曲家的软件包，找不到类

Question

我创建了一个作曲家程序包，但是当我在Laravel中使用它时，出现以下错误：

Class 'Markok\Example_for_composer\Example_for_composer' not found 

我的控制器：

use Markok\Example_for_composer\Example_for_composer;
    class NotesController extends Controller
    {
        public function index()
        {
            $a = new Example_for_composer();
            $a->greet("Mark");
        }
    }

Composer.json：

"autoload": {
    "psr-4": {
        "App\\": "app/",
        "Markok\\Example_for_composer\\": "packages/markok/example_for_composer/src"
    },
    "classmap": [
        "database/seeds",
        "database/factories"
    ]
},

markok / example_for_composer / src / Example_for_composer.php：

<?php
namespace Markok\Example_for_composer;

class Example_for_composer
{
    public function greet(String $sName)
    {
        return 'Hi ' . $sName . '! How are you doing today?';
    }
}

可能是什么问题？