keyList.count++;
      node.previous = nextSibling.previous;
      node.previousSibling = nextSibling.previousSibling;
      node.next = nextSibling;
      node.nextSibling = nextSibling;
      if (nextSibling.previousSibling == null) { // nextSibling was key head
        keyList.head = node;
      } else {
        nextSibling.previousSibling.nextSibling = node;
      }