Overtrue\Validation\Validator::validateDate PHP Method

    protected function validateDate($attribute, $value)
    {
        if ($value instanceof DateTime) {
            return true;
        }
        if (strtotime($value) === false) {
            return false;
        }
        $date = date_parse($value);
        return checkdate($date['month'], $date['day'], $date['year']);
    }