mageekguy\atoum\asserters\dateTime::valueIsSet PHP Метод

    protected function valueIsSet($message = null)
    {
        $message = $message ?: 'Value is not an instance of \\dateTime or \\dateTimeInterface';
        if (self::isDateTime(parent::valueIsSet($message)->value) === false) {
            throw new exceptions\logic($message);
        }
        return $this;
    }