Yii2 - Class 'koolreport\KoolReport' not found

[alejosv]

When I load MyReport class have this error

Class 'koolreport\KoolReport' not found

<?php
namespace app\reports;

class MyReport extends \koolreport\KoolReport
{
... 

I installed the package with composer: composer require koolreport/yii2

[alejosv]

My fault, I didn't install the core package.