ListBuilder/DynamicListBuilder.php
public function build(Dynamic $dynamic, $locale)
    {
        $entry = $dynamic->getFields();

        $singleEntry = [
            'id' => $dynamic->getId(),
        ];

        foreach ($entry as $key => $value) {
            if (Dynamic::TYPE_ATTACHMENT === $dynamic->getFieldType($key)) {
                $singleEntry[$key] = $this->getMediaUrls($value);
            } else {
                $singleEntry[$key] = $this->toString($value);
            }
        }

        $singleEntry['created'] = $dynamic->getCreated()->format('c');

        return [$singleEntry];
    }
public function build(Dynamic $dynamic, $locale)
    {
        $entry = $dynamic->getFields();

        $singleEntry = [
            'id' => $dynamic->getId(),
        ];

        foreach ($entry as $key => $value) {
            if (Dynamic::TYPE_ATTACHMENT === $dynamic->getFieldType($key)) {
                $singleEntry[$key] = $this->getMediaUrls($value);
            } else {
                $singleEntry[$key] = $this->toString($value);
            }
        }

        $singleEntry['created'] = $dynamic->getCreated()->format('c');

        return [$singleEntry];
    }
@param Dynamic $dynamic
@param $locale

@return array