@Override
    public boolean equals(Object other) {
      if (!other.getClass().equals(getClass())) {
        return false;
      }

      if (other == this) {
        return true;
      }

      return ((ServiceCheckStageWrapper) other).service.equals(service);

    }
Special type of stage wrapper that allows inspection of the service check for
merging if required.  This prevents consecutive service checks from running, particularly
for Patch or Maintenance types of upgrades.
ambari-server/src/main/java/org/apache/ambari/server/stack/upgrade/ServiceCheckGrouping.java