code: def nla_put_string(msg, attrtype, value):
      
      data = bytearray(value) + bytearray(b'\0')
      return nla_put(msg, attrtype, len(data), data)
docs: Add string attribute to Netlink message.
  
      https://github.com/thom311/libnl/blob/libnl3_2_25/lib/attr.c#L674
  
      Positional arguments:
      msg -- Netlink message (nl_msg class instance).
      attrtype -- attribute type (integer).
      value -- bytes() or bytearray() value (e.g. 'Test'.encode('ascii')).
  
      Returns:
      0 on success or a negative error code.