code: def nla_put_nested(msg, attrtype, nested):
      
      _LOGGER.debug('msg 0x%x: attr <> %d: adding msg 0x%x as nested attribute', id(msg), attrtype, id(nested))
      return nla_put(msg, attrtype, nlmsg_datalen(nested.nm_nlh), nlmsg_data(nested.nm_nlh))
docs: Add nested attributes to Netlink message.
  
      https://github.com/thom311/libnl/blob/libnl3_2_25/lib/attr.c#L772
  
      Takes the attributes found in the `nested` message and appends them to the message `msg` nested in a container of
      the type `attrtype`. The `nested` message may not have a family specific header.
  
      Positional arguments:
      msg -- Netlink message (nl_msg class instance).
      attrtype -- attribute type (integer).
      nested -- message containing attributes to be nested (nl_msg class instance).
  
      Returns:
      0 on success or a negative error code.