code: function () {
          // we unlink every member from it's parent (assuming this is their parent)
          this.all().forEach(PropertyList._unlinkItemFromParent);
  
          this.members.length = 0; // remove all items from list
  
          // now we remove all items from index reference
          Object.keys(this.reference).forEach(function (key) {
              delete this.reference[key];
          }.bind(this));
      }
docs: Removes all items in the list