url_downloader = downloader.PackageFileDownloader(url, "1", "/", "VNFD", proxy)
download_id = yield from self.job_handler.register_downloader(url_downloader)
assert download_id is not None
url_downloader = downloader.PackageFileDownloader(url, "1", "/", "VNFD", proxy)
download_id = yield from self.job_handler.register_downloader(url_downloader)
assert download_id is not None