docs: def _exec_ipmitool(driver_info, command):
      """Execute the ipmitool command.
  
      This uses the lanplus interface to communicate with the BMC device driver.
  
      :param driver_info: the ipmitool parameters for accessing a node.
      :param command: the ipmitool command to be executed.
  
      """
      ipmi_cmd = ("ipmitool -H %(address)s"
                  " -I lanplus -U %(user)s -P %(passwd)s %(cmd)s"
                  % {'address': driver_info['address'],
                     'user': driver_info['username'],
                     'passwd': driver_info['password'],
                     'cmd': command})
  
      out = None
      try:
          out = subprocess.check_output(ipmi_cmd, shell=True)
      except Exception:
          pass
      return out