code: public int run() throws IOException {
      List<WorkerLostStorageInfo> workerLostStorageList = mBlockMasterClient.getWorkerLostStorage();
      if (workerLostStorageList.size() == 0) {
        mPrintStream.println("All worker storage paths are in working state.");
        return 0;
      }
      for (WorkerLostStorageInfo info : workerLostStorageList) {
        Map<String, StorageList> lostStorageMap = info.getLostStorageMap();
        if (lostStorageMap.size() != 0) {
          mPrintStream.printf("The following storage paths are lost in worker %s: %n",
              info.getAddress().getHost());
          for (Map.Entry<String, StorageList> tierStorage : lostStorageMap.entrySet()) {
            for (String storage : tierStorage.getValue().getStorageList()) {
              mPrintStream.printf("%s (%s)%n", storage, tierStorage.getKey());
            }
          }
        }
      }
      return 0;
    }
docs: Runs doctor storage command.
  
  @return 0 on success, 1 otherwise