/**
  * @param string $pattern
  * @param bool $saveSymbolsOnly
  * @param IDateTimeFixer|NULL $dateTimeFixer
  */
 public function __construct($pattern, $saveSymbolsOnly = self::SAVE_SYMBOLS_ONLY, IDateTimeFixer $dateTimeFixer = NULL)
 {
     if ($saveSymbolsOnly) {
         Tools::checkPattern($pattern);
     }
     $this->pattern = $pattern;
     $this->dateTimeFixer = $dateTimeFixer !== NULL ? $dateTimeFixer : new SimplePatternParsingFixer();
 }