code: def CallDhclient(
      interfaces, logger, dhclient_script=None):
    
    logger.info('Enabling the Ethernet interfaces %s.', interfaces)
  
    dhclient_command = ['dhclient']
  
    if dhclient_script and os.path.exists(dhclient_script):
      dhclient_command += ['-sf', dhclient_script]
  
    try:
      subprocess.check_call(dhclient_command + ['-x'] + interfaces)
      subprocess.check_call(dhclient_command + interfaces)
    except subprocess.CalledProcessError:
      logger.warning('Could not enable interfaces %s.', interfaces)
docs: Configure the network interfaces using dhclient.
  
    Args:
      interfaces: list of string, the output device names to enable.
      logger: logger object, used to write to SysLog and serial port.
      dhclient_script: string, the path to a dhclient script used by dhclient.