code: def _guess_iface_name(netif):
      
      with os.popen('%s -l' % conf.prog.ifconfig) as fdesc:
          ifaces = fdesc.readline().strip().split(' ')
      matches = [iface for iface in ifaces if iface.startswith(netif)]
      if len(matches) == 1:
          return matches[0]
      return None
docs: We attempt to guess the name of interfaces that are truncated from the
      output of ifconfig -l.
      If there is only one possible candidate matching the interface name then we
      return it.
      If there are none or more, then we return None.