How to use the pulpcore.plugin.stages.DeclarativeContent function in pulpcore

async def _handle_component(self, component, release, release_file, file_references):
        # Create release_component
        release_component_dc = DeclarativeContent(
            content=ReleaseComponent(component=component, release=release)
        )
        release_component = await self._create_unit(release_component_dc)
        architectures = _filter_split(release_file.architectures, self.architectures)
        pending_tasks = []
        # Handle package indices
        pending_tasks.extend(
            [
                self._handle_package_index(
                    release_file, release_component, architecture, file_references
                )
                for architecture in architectures
            ]
        )
        # Handle installer package indices
        if self.remote.sync_udebs:

# Create release_file
        release_file_dc = DeclarativeContent(
            content=ReleaseFile(distribution=distribution),
            d_artifacts=[
                self._to_d_artifact(os.path.join("dists", distribution, filename))
                for filename in ["Release", "InRelease", "Release.gpg"]
            ],
        )
        release_file = await self._create_unit(release_file_dc)
        if release_file is None:
            return
        # Create release object
        release_unit = Release(
            codename=release_file.codename, suite=release_file.suite, distribution=distribution
        )
        release_dc = DeclarativeContent(content=release_unit)
        release = await self._create_unit(release_dc)
        # Create release architectures
        for architecture in _filter_split(release_file.architectures, self.architectures):
            release_architecture_dc = DeclarativeContent(
                content=ReleaseArchitecture(architecture=architecture, release=release)
            )
            await self.put(release_architecture_dc)
        # Parse release file
        log.info('Parsing Release file for release: "{}"'.format(release_file.codename))
        release_file_dict = deb822.Release(release_file.main_artifact.file)
        # collect file references in new dict
        file_references = defaultdict(deb822.Deb822Dict)
        for digest_name in ["SHA512", "SHA256", "SHA1", "MD5sum"]:
            if digest_name in release_file_dict:
                for unit in release_file_dict[digest_name]:
                    file_references[unit["Name"]].update(unit)

digest=digest,
        )
        url = urljoin(self.remote.url, relative_url)
        manifest_list = Manifest(
            digest=digest,
            schema_version=manifest_list_data['schemaVersion'],
            media_type=manifest_list_data['mediaType'],
        )
        da = DeclarativeArtifact(
            artifact=tag_dc.d_artifacts[0].artifact,
            url=url,
            relative_path=digest,
            remote=self.remote,
            extra_data={'headers': V2_ACCEPT_HEADERS}
        )
        list_dc = DeclarativeContent(content=manifest_list, d_artifacts=[da])

        return list_dc

elif record.type not in PACKAGE_DB_REPODATA:
                    file_data = {record.checksum_type: record.checksum, "size": record.size}
                    da = DeclarativeArtifact(
                        artifact=Artifact(**file_data),
                        url=urljoin(remote_url, record.location_href),
                        relative_path=record.location_href,
                        remote=self.remote,
                        deferred_download=False
                    )
                    repo_metadata_file = RepoMetadataFile(
                        data_type=record.type,
                        checksum_type=record.checksum_type,
                        checksum=record.checksum,
                    )
                    dc = DeclarativeContent(content=repo_metadata_file, d_artifacts=[da])
                    await self.put(dc)

            missing_type = set(PACKAGE_REPODATA) - main_types
            if missing_type:
                raise FileNotFoundError(_("XML file(s): {filename} not found").format(
                    filename=", ".join(missing_type)))

            # we have to sync module.yaml first if it exists, to make relations to packages
            if modulemd_results:
                modulemd_index = mmdlib.ModuleIndex.new()
                open_func = gzip.open if modulemd_results.url.endswith('.gz') else open
                with open_func(modulemd_results.path, 'r') as moduleyaml:
                    modulemd_index.update_from_string(
                        moduleyaml.read().decode(), True
                    )

if filename in InstallerFileIndex.FILE_ALGORITHM:  # strangely they may appear here
                    continue
                file_list[filename][algorithm] = digest

        for filename, digests in file_list.items():
            relpath = os.path.join(installer_file_index.relative_path, filename)
            urlpath = os.path.join(self.parsed_url.path, relpath)
            content_unit = GenericContent(sha256=digests["sha256"], relative_path=relpath)
            d_artifact = DeclarativeArtifact(
                artifact=Artifact(**digests),
                url=urlunparse(self.parsed_url._replace(path=urlpath)),
                relative_path=relpath,
                remote=self.remote,
                deferred_download=deferred_download,
            )
            d_content = DeclarativeContent(content=content_unit, d_artifacts=[d_artifact])
            await self.put(d_content)

media_type=blob_data.get('mediaType', MEDIA_TYPE.REGULAR_BLOB),
        )
        relative_url = '/v2/{name}/blobs/{digest}'.format(
            name=self.remote.namespaced_upstream_name,
            digest=digest,
        )
        blob_url = urljoin(self.remote.url, relative_url)
        da = DeclarativeArtifact(
            artifact=blob_artifact,
            url=blob_url,
            relative_path=digest,
            remote=self.remote,
            extra_data={'headers': V2_ACCEPT_HEADERS},
            deferred_download=self.deferred_download
        )
        blob_dc = DeclarativeContent(
            content=blob,
            d_artifacts=[da],
        )

        return blob_dc

paths = [path for path in file_references.keys() if path.startswith(translation_dir)]
        translations = {}
        for path in paths:
            relative_path = os.path.join(os.path.dirname(release_file.relative_path))
            d_artifact = self._to_d_artifact(relative_path, file_references[path])
            key, ext = os.path.splitext(relative_path)
            if key not in translations:
                translations[key] = {"sha256": None, "d_artifacts": []}
            if not ext:
                translations[key]["sha256"] = d_artifact.artifact.sha256
            translations[key]["d_artifacts"].append(d_artifact)

        for relative_path, translation in translations.items():
            content_unit = GenericContent(sha256=translation["sha256"], relative_path=relative_path)
            await self.put(
                DeclarativeContent(content=content_unit, d_artifacts=translation["d_artifacts"])
            )

deferred_download=deferred_download,
                )
                package_dc = DeclarativeContent(
                    content=package_content_unit, d_artifacts=[package_da]
                )
                package_futures.append(package_dc)
                await self.put(package_dc)
            except KeyError:
                log.warning("Ignoring invalid package paragraph. {}".format(package_paragraph))
        # Assign packages to this release_component
        for package_future in package_futures:
            package = await package_future.resolution()
            if not isinstance(package, Package):
                # TODO repeat this for installer packages
                continue
            package_release_component_dc = DeclarativeContent(
                content=PackageReleaseComponent(
                    package=package, release_component=release_component
                )
            )
            await self.put(package_release_component_dc)

if self.treeinfo:
                d_artifacts = []
                for path, checksum in self.treeinfo["download"]["images"].items():
                    artifact = Artifact(**checksum)
                    da = DeclarativeArtifact(
                        artifact=artifact,
                        url=urljoin(remote_url, path),
                        relative_path=path,
                        remote=self.remote,
                        deferred_download=self.deferred_download
                    )
                    d_artifacts.append(da)

                distribution_tree = DistributionTree(**self.treeinfo["distribution_tree"])
                dc = DeclarativeContent(content=distribution_tree, d_artifacts=d_artifacts)
                dc.extra_data = self.treeinfo
                await self.put(dc)

            repomd_path = result.path
            repomd = cr.Repomd(repomd_path)
            package_repodata_urls = {}
            downloaders = []
            modulemd_list = list()
            dc_groups = []
            dc_categories = []
            dc_environments = []
            nevra_to_module = defaultdict(dict)
            pkgname_to_groups = defaultdict(list)
            group_to_categories = defaultdict(list)
            group_to_environments = defaultdict(list)
            optionalgroup_to_environments = defaultdict(list)