class ListDataFormatter implements FormatterInterface
{
   /**
    * Checks object for needed requirements.
    *
    * @var FormatterSpecificationInterface $specification
    */
   private $specification;

   /**
    * ListDataFormatter constructor.
    *
    * @param FormatterSpecificationInterface $specification
    */
   public function __construct(FormatterSpecificationInterface $specification)
   {
       $this->specification = $specification;
   }

  /**
   * {@inheritdoc}
   */
  public function format(ResponseDtoInterface $data)
   {
       if ($this->specification->isSatisfiedBy($data)) {
           $data = $data->getData();
       }

       return $data;
   }
}