code: @Override
      public void setAttempts(String projectId, String eventCollection, String attemptsString) {
          if (attempts == null) {
              attempts = new HashMap<String, Map<String, String>>();
          }
  
          Map<String, String> project = attempts.get(projectId);
          if (project == null) {
              project = new HashMap<String, String>();
              attempts.put(projectId, project);
          }
  
          project.put(eventCollection, attemptsString);
      }
docs: {@inheritDoc}