code: function(terria) {
    CatalogMember.call(this, terria);
  
    this._loadingPromise = undefined;
    this._lastLoadInfluencingValues = undefined;
    this._parameters = [];
  
    /**
     * Gets or sets a value indicating whether the group is currently loading.  This property
     * is observable.
     * @type {Boolean}
     */
    this.isLoading = false;
  
    /**
     * A catalog item that will be enabled while preparing to invoke this catalog function, in order to
     * provide context for the function.
     * @type {CatalogItem}
     */
    this.contextItem = undefined;
  
    knockout.track(this, ["isLoading"]);
  }
docs: A member of a catalog that does some kind of parameterized processing or analysis.
  
  @alias CatalogFunction
  @constructor
  @extends CatalogMember
  @abstract
  
  @param {Terria} terria The Terria instance.