ListExtensions

Available Extensions
Clone
AddIfNotExists
UpdateValue
DeleteIfExists
AreValuesNull

Example

var dupList = list.Clone();

//

list.AddIfNotExists(item);

//

list.UpdateValue(item, newItem);

//

list.DeleteIfExists(item);

//

bool areNull = list.AreValuesNull();

Demo

you can run demo and see this feature.