code: function findClusterByAddinId(id) {
          var i, j;
          var clusters;
          for (j = 1; j < arguments.length; j++) {
              clusters = arguments[j];
              for (i = 0; i < clusters.length; i++) {
                  if (clusters[i].containsAddin(id)) {
                      return clusters[i];
                  }
              }
          }
  
          return null;
      }
docs: /*
  Returns a cluster that contains an addin with the given id or null if no cluster contains this id