docs: def retrieve_sources():
      """Retrieve sources using spectool
      """
      spectool = find_executable('spectool')
      if not spectool:
          log.warn('spectool is not installed')
          return
      try:
          specfile = spec_fn()
      except Exception:
          return
  
      cmd = [spectool, "-g", specfile]
      output = subprocess.check_output(' '.join(cmd), shell=True)
      log.warn(output)