code: public function init()
      {
          parent::init();
          if (!isset($this->translations['yii']) && !isset($this->translations['yii*'])) {
              $this->translations['yii'] = [
                  'class' => 'yii\i18n\PhpMessageSource',
                  'sourceLanguage' => 'en-US',
                  'basePath' => '@yii/messages',
              ];
          }
  
          if (!isset($this->translations['app']) && !isset($this->translations['app*'])) {
              $this->translations['app'] = [
                  'class' => 'yii\i18n\PhpMessageSource',
                  'sourceLanguage' => Yii::$app->sourceLanguage,
                  'basePath' => '@app/messages',
              ];
          }
      }
docs: Initializes the component by configuring the default message categories.