$tz = @timezone_open($object = (string) $object);
 
        if ($tz !== false) {
            return $tz;
        }
 
        // Work-around for a bug fixed in PHP 5.5.10 https://bugs.php.net/bug.php?id=45528
        // See: https://stackoverflow.com/q/14068594/2646927
        // @codeCoverageIgnoreStart
        if (strpos($object, ':') !== false) {
            try {
                return static::createFromFormat('O', $object)->getTimezone();
            } catch (InvalidArgumentException $e) {
                //
            }
        }
        // @codeCoverageIgnoreEnd
 
        throw new InvalidArgumentException('Unknown or bad timezone ('.$object.')');
    }
 
    ///////////////////////////////////////////////////////////////////
    //////////////////////////// CONSTRUCTORS /////////////////////////
    ///////////////////////////////////////////////////////////////////
 
    /**
     * Create a new Carbon instance.
     *
     * Please see the testing aids section (specifically static::setTestNow())
     * for more on the possibility of this constructor returning a test instance.
     *
     * @param string|null               $time
     * @param \DateTimeZone|string|null $tz
     */
    public function __construct($time = null, $tz = null)
    {
        // If the class has a test now set and we are trying to create a now()
        // instance then override as required
        $isNow = empty($time) || $time === 'now';