code: def download_file_job(entry, directory, checksums, filetype='genbank', symlink_path=None):
      
      pattern = NgdConfig.get_fileending(filetype)
      filename, expected_checksum = get_name_and_checksum(checksums, pattern)
      base_url = convert_ftp_url(entry['ftp_path'])
      full_url = '{}/{}'.format(base_url, filename)
      local_file = os.path.join(directory, filename)
      full_symlink = None
      if symlink_path is not None:
          full_symlink = os.path.join(symlink_path, filename)
  
      # Keep metadata around
      mtable = metadata.get()
      mtable.add(entry, local_file)
  
      return DownloadJob(full_url, local_file, expected_checksum, full_symlink)
docs: Generate a DownloadJob that actually triggers a file download.