code: public static Set<Collection<VM>> requiredVMPart(Model mo, JSONObject o, String id) throws JSONConverterException {
          Set<Collection<VM>> vms = new HashSet<>();
          Object x = o.get(id);
          if (!(x instanceof JSONArray)) {
              throw new JSONConverterException("Set of identifiers sets expected at key '" + id + "'");
          }
          for (Object obj : (JSONArray) x) {
              vms.add(vmsFromJSON(mo, (JSONArray) obj));
          }
          return vms;
      }
docs: Read partitions of VMs.
  
  @param mo the associated model to browse
  @param o  the object to parse
  @param id the key in the map that points to the partitions
  @return the parsed partition
  @throws JSONConverterException if the key does not point to partitions of VMs