docs: function (child, parent, property) {
                  if (__isValidContainer(child)) {
                      this.__checkBackRefs(child);
                      // add a reference to the parent in the new property
                      child[parProp].push({
                          parent : parent,
                          property : property
                      });
                      this.$raiseEvent({
                          name : 'aria-parent-metadata-added',
                          child: child,
                          parent: parent,
                          property: property
                      });
                  }
              }