code: private void addLeaf(Segment10 segment,
                         int pid, 
                         int nextPid,
                         int address,
                         int length)
    {
      Page10 page = _pageMap.get(pid);
      
      if (page != null && page.sequence() < segment.sequence()) {
        return;
      }
      
      page = new Page10(PageType10.LEAF, segment, pid, nextPid, address, length);
      
      _pageMap.put(pid, page);
    }
docs: Adds a new leaf entry to the page list.
  
  Because pages are added in order, each new page overrides the older one.