public void removeCommandFromHistory(List<ICommand> commands) {
   for (ICommand.CommandTag tag : ICommand.CommandTag.values()) {
     commandTagListHashMap.get(tag).removeAll(commands);
   }
 }
 public CommandTagListMap() {
   for (ICommand.CommandTag tag : ICommand.CommandTag.values()) {
     commandTagListHashMap.put(tag, new ArrayList<ICommand>());
   }
 }