code: public Map<String,Object> restore(PersistenceContext ctx, byte nodeId) {
          Map<String,Object> map = ctx.getCommandClassMap(nodeId, getId());
          this.version = (int)map.get("version");
          return map;
      }
docs: Restores details about this command class from a persistence context.
  
  @param ctx the persistence context
  @param nodeId the node ID associated with this command class
  
  @return a Map with the command class properties