code: func (flag *NetworkFlag) Change(device types.BaseVirtualDevice, update types.BaseVirtualDevice) {
  	current := device.(types.BaseVirtualEthernetCard).GetVirtualEthernetCard()
  	changed := update.(types.BaseVirtualEthernetCard).GetVirtualEthernetCard()
  
  	current.Backing = changed.Backing
  
  	if changed.MacAddress != "" {
  		current.MacAddress = changed.MacAddress
  	}
  
  	if changed.AddressType != "" {
  		current.AddressType = changed.AddressType
  	}
  }
docs: // Change applies update backing and hardware address changes to the given network device.