code: void add( LessExtend lessExtend, String[] mainSelector ) {
          if( mainSelector == null || mainSelector[0].startsWith( "@media" ) ) {
              mainSelector = lessExtend.getSelectors();
          } else {
              mainSelector = SelectorUtils.merge( mainSelector, lessExtend.getSelectors() );
          }
          String extendingSelector = lessExtend.getExtendingSelector();
          if( lessExtend.isAll() ) {
              LessExtendResult extend = new LessExtendResult( mainSelector, extendingSelector );
              SelectorTokenizer tokenizer = tokenizers.pollLast().init( extendingSelector );
              do {
                  String token = tokenizer.next();
                  if( token == null ) {
                      break;
                  }
                  all.add( token, extend );
              } while( true );
              tokenizers.addLast( tokenizer );
          } else {
              exact.add( extendingSelector, mainSelector );
          }
      }
docs: Is calling on formatting if an extends was include.
  @param lessExtend the extend
  @param mainSelector the selectors in which the extend is placed.