public void test()
{
IRoseTree <string, Command> editMenu =
from name in editMenuTemplate
select commandStore.Lookup(name).GetOrElse(new Command(name));
Maybe <Command> find;
using StringWriter sw = new StringWriter();
Console.SetOut(sw);
find = editMenu.Find(e => e.Name == "Find");
var findAll = editMenu.FindAll(e => e.Name == "Find" || e.Name == "Copy");
var concat = editMenu.Fold((acc, c) => acc + c.Name, "");
find.Match(Nothing: () => { }, Just: c => c.Execute());
Assert.Equal($"Find\r\n", sw.ToString());
}