code: function UMLActivity() {
          UMLBehavior.apply(this, arguments);
  
          /** @member {boolean} */
          this.isReadOnly = false;
  
          /** @member {boolean} */
          this.isSingleExecution = false;
  
          /** @member {Array.<UMLActivityNode>} */
          this.nodes = [];
  
          /** @member {Array.<UMLActivityEdge>} */
          this.edges = [];
  
          /** @member {Array.<UMLActivityGroup>} */
          this.groups = [];
      }
docs: ************************************************************************
  *
  ACTIVITIES                              *
  *
  ************************************************************************ 
  UMLActivity
  @constructor
  @extends UMLActivity