code: function UMLDirectedRelationship() {
          type.DirectedRelationship.apply(this, arguments);
  
          /** @member {UMLStereotype} */
          this.stereotype = null;
  
          /** @member {string} */
          this.visibility = VK_PUBLIC;
          // mixin UMLElementMixin
          _.extend(UMLDirectedRelationship.prototype, UMLElementMixin);
      }
docs: UMLDirectedRelationship
  @constructor
  @extends DirectedRelationship
  @mixes UMLElementMixin