code: public static Map<String, String> getTopologyCodeLocations(
              Map<String, Assignment> assignments, String supervisorId) throws Exception {
          Map<String, String> rtn = new HashMap<>();
          for (Entry<String, Assignment> entry : assignments.entrySet()) {
              String topologyId = entry.getKey();
              Assignment assignmentInfo = entry.getValue();
  
              Set<ResourceWorkerSlot> workers = assignmentInfo.getWorkers();
              for (ResourceWorkerSlot worker : workers) {
                  String node = worker.getNodeId();
                  if (supervisorId.equals(node)) {
                      rtn.put(topologyId, assignmentInfo.getMasterCodeDir());
                      break;
                  }
              }
  
          }
          return rtn;
      }
docs: get master code dir for each topology
  
  @return Map: [topologyId, master-code-dir] from zookeeper