Add item from List Document to another list

Hello

I try add document from one list to another and have error unsupported operation add.

i have List<StoreRecord> store as argument to function, after some operation i need add item from this list to another.

List<StoreRecord> result = List<StoreRecord>.empty();

for (var item in store) {

...

result.add(item)

}

code compilation, but when testing have error unsupported operation add