code: public List<Command> removeFromMap(final UUID mapId, final Object key) {
          final State state = createCommandList(new WithCommandType() {
              @Override
              public void invoke(final State state) {
                  createObservableObject(key, state);
              }
          }, false);
  
          final boolean keyIsObservableObject = state.lastObjectWasObservable;
  
          final RemoveFromMap msg = new RemoveFromMap();
          msg.setMapId(mapId);
          msg.setKey(valueMapper.map(key, keyIsObservableObject));
  
          state.commands.add(state.commands.size() - 1, msg);
          return state.commands;
      }
docs: Creates the list with command necessary to remove a mapping from a map.
  
  @param mapId
  the map where the mapping should be removed.
  @param key
  the key of the mapping that should be removed.
  @return the list with the commands.