docs: function (subSection) {
                  this.$assert(141, !subSection.parent);
                  this.$assert(142, subSection._type == TYPE_SECTION);
                  this.$assert(143, subSection.tplCtxt == this.tplCtxt);
                  subSection.parent = this;
                  subSection.__updateIdMap(this.idMap);
                  this._content.push(subSection);
              }