gistfile1.php

<?php

namespace app\modules\MY-MODULE;

class Module extends \yii\base\Module
{
    public $controllerNamespace = 'app\modules\MY-MODULE\controllers';

    public function init()
    {
        parent::init();

        // Declare services. Let's say you need the XmlService.
        $this->set('xml', new services\XmlService());

    }
}