code: public static void assertServerNotInOfflineState(AdminClient adminClient,
                                                       Collection<Integer> nodeIds) {
          assertServerState(adminClient, nodeIds, VoldemortState.OFFLINE_SERVER, false);
      }
docs: Utility function that checks the execution state of the server by
  checking the state of {@link VoldemortState} <br>
  
  This function checks if the nodes are not in offline state (
  {@link VoldemortState#OFFLINE_SERVER}).
  
  @param adminClient An instance of AdminClient points to given cluster
  @param nodeIds List of node ids to be checked
  @throws VoldemortException if any node is in offline state