anchor.diff:      return handlers.keys.contains(type) ? handlers[type] : null;
     }
   
  +  /**
  +   * add post constructor
  +   */
  +   // TODO : define use cases
     void addHandler(Request a, CommandBuilder<AbstractModel> constructor) {
       handlers[a.actionType] = constructor;
     }
  
positive.code:  * listen to dispatcher's stream of actions and map them to commands, executed on the store
   */
  class Commander {
    CommanderConfig config;
  
    Store<AbstractModel> store;
  
    Dispatcher dispatcher;
  
    Commander(CommanderConfig this.config, Store<AbstractModel> this.store,
        Dispatcher this.dispatcher) {
      dispatcher.onDispatch.listen((Request a) => handle(a));
    }
  
    cancel() => store.cancel();
  
    _exec(Command<AbstractModel> c) {
      store.update(c);
    }
  
    handle(Request a) {
      var handler = this.config.getHandler(a.actionType);
      try{
        _exec(handler(a.value));
      } catch (err){
        print('Commander.handle... No command defined for this Action ${a} \n $err');
      }
  
negative.code:   Map<A, CommandBuilder<AbstractModel>> handlers;
  
    /**
     * RequestTypes / CommandBuilders mapping injection
     */
    CommanderConfig(Map<A, CommandBuilder> map) {
      handlers = map;
  