/**
  * Returns the default instance.
  *
  * @return PHP_CodeCoverage
  */
 public static function getInstance()
 {
     if (self::$instance === NULL) {
         // @codeCoverageIgnoreStart
         self::$instance = new PHP_CodeCoverage();
     }
     // @codeCoverageIgnoreEnd
     return self::$instance;
 }