code: func (m *OuiDb) VendorLookup(s string) (string, error) {
  	addr, err := net.ParseMAC(s)
  	if err != nil {
  		return "", err
  	}
  	block := m.Lookup(HardwareAddr(addr))
  	if block == nil {
  		return "", ErrInvalidMACAddress
  	}
  	return block.Organization, nil
  }
docs: // VendorLookup obtains the vendor organization name from the MAC address s.