docs: public TokenList extractSubList( Token begin , Token end ) {
          if( begin == end ) {
              remove(begin);
              return new TokenList(begin,begin);
          } else {
              if( first == begin ) {
                  first = end.next;
              }
              if( last == end ) {
                  last = begin.previous;
              }
              if( begin.previous != null ) {
                  begin.previous.next = end.next;
              }
              if( end.next != null ) {
                  end.next.previous = begin.previous;
              }
              begin.previous = null;
              end.next = null;
  
              TokenList ret = new TokenList(begin,end);
              size -= ret.size();
              return ret;
          }
      }