trait MagicDataSet
{
    public function getAttributeValue(string $attribute)
    {
        if (!$this->hasAttribute($attribute)) {
            throw new MissingAttributeException('$attribute is missing');
        }

        return get_object_vars($this)[$attribute];
    }

    public function hasAttribute(string $attribute): bool
    {
        return array_key_exists($attribute, get_object_vars($this));
    }
}

class Post implements DataSetInterface
{
    use MagicDataSet;

    public string $title;
    public string $description;
}