code: function(type, priority) {
  			if (!this._annotationTypes) { this._annotationTypes = []; }
  			var index = priority - 1;
  			if (priority == undefined || !(0 <= index && index < this._annotationTypes.length)) {
  				this._annotationTypes.push(type);
  			} else {
  				this._annotationTypes.splice(index, 0, type);
  			}
  		}
docs: Adds an annotation type to the receiver.
  <p>
  Only annotations of the specified types will be shown by
  the receiver.
  </p>
  <p>
  If the priority is not specified, the annotation type will be added
  to the end of the receiver's list (lowest pririoty).
  </p>
  
  @param {Object} type the annotation type to be shown
  @param {Number} priority the priority for the annotation type
  
  @see orion.editor.AnnotationTypeList#removeAnnotationType
  @see orion.editor.AnnotationTypeList#isAnnotationTypeVisible
  @see orion.editor.AnnotationTypeList#getAnnotationTypePriority