/**
  * Returns the singleton instance
  *
  * @return MimeTypeGuesser
  */
 public static function getInstance()
 {
     if (null === self::$instance) {
         self::$instance = new self();
     }
     return self::$instance;
 }
 /**
  * Returns the singleton instance
  *
  * @return MimeTypeGuesser
  */
 public static function getInstance()
 {
     if (is_null(self::$instance)) {
         self::$instance = new self();
     }
     return self::$instance;
 }
 /**
  * Resets the singleton instance.
  */
 public static function reset()
 {
     self::$instance = null;
 }