docs: def list_presets(cfg, out=sys.stdout):
      """Write a human readable list of available presets to out.
  
      :param cfg: ConfigParser instance
      :param out: file object to write to
      """
      for section in cfg.sections():
          if section.startswith("preset:"):
              out.write((section.replace("preset:", "")) + os.linesep)
              for k, v in cfg.items(section):
                  out.write("\t%s = %s" % (k, v) + os.linesep)