public function getCollectionAction(Request $request, $start, $count, Page $parent = null)
    {
        $response = null;
        $contentUid = $request->query->get('content_uid', null);
        $contentType = $request->query->get('content_type', null);

        if (null !== $contentUid && null !== $contentType) {
            $response = $this->doGetCollectionByContent($contentType, $contentUid);
        } elseif ((null === $contentUid && null !== $contentType) || (null !== $contentUid && null === $contentType)) {
            throw new BadRequestHttpException(
                'To get page collection by content, you must provide `content_uid` and `content_type` as query parameters.'
            );
        } elseif ($request->attributes->get('version') == 1) {
            $response = $this->doClassicGetCollectionVersion1($request, $start, $count, $parent);
        } else {
            $response = $this->doClassicGetCollection($request, $start, $count, $parent);
        }

        return $response;
    }