constructor(
    options,
    body,
    imagelist,
    grouplist,
    globalOptions,
    defaultOptions
  ) {
    super(options, body, imagelist, grouplist, globalOptions, defaultOptions);

    this.isCluster = true;
    this.containedNodes = {};
    this.containedEdges = {};
  }
@param {object} options
@param {object} body
@param {Array.<HTMLImageElement>}imagelist
@param {Array} grouplist
@param {object} globalOptions
@param {object} defaultOptions     Global default options for nodes