code: func MsglvlSet(intf string, valset uint32) (uint32, uint32, error) {
  	e, err := NewEthtool()
  	if err != nil {
  		return 0, 0, err
  	}
  	defer e.Close()
  	return e.MsglvlSet(intf, valset)
  }
docs: // MsglvlSet returns the read-msglvl, post-set-msglvl of the given interface.