code: protected static function loadMimeTypes($magicFile)
      {
          if ($magicFile === null) {
              $magicFile = static::$mimeMagicFile;
          }
          $magicFile = Yii::getAlias($magicFile);
          if (!isset(self::$_mimeTypes[$magicFile])) {
              self::$_mimeTypes[$magicFile] = require $magicFile;
          }
  
          return self::$_mimeTypes[$magicFile];
      }
docs: Loads MIME types from the specified file.
  @param string $magicFile the path (or alias) of the file that contains all available MIME type information.
  If this is not set, the file specified by [[mimeMagicFile]] will be used.
  @return array the mapping from file extensions to MIME types