code: @Override
      protected List<UniqueKey<? extends Command>> defineSubCommand() {
          // for (Object keyPart : getListKeyPart()) {
  
          // if (keyPart instanceof GroupRef) {
  
          final List<UniqueKey<? extends Command>> commandList = new ArrayList<>();
  
          // GroupRef groupRef = (GroupRef) keyPart;
          final GroupRef groupRef = getKeyPart(GroupRef.class);
  
          setSequential(groupRef.sequential());
  
          this.runIntoThread = groupRef.runInto();
          this.runnablePriority = groupRef.priority();
  
          for (final Ref ref : groupRef.children()) {
              if (ref instanceof GroupRef) {
                  commandList.add(getCommandKey(GroupRefCommand.class, ref));
              } else if (ref instanceof SingleRef) {
                  commandList.add(getCommandKey(RefCommand.class, ref));
              } else if (ref instanceof RealRef) {
                  commandList.add(((RealRef) ref).key());
              }
          }
  
          return commandList;
          // break;
          // }
          // }
      }
docs: {@inheritDoc}