code: func simpleNthLastChildSelector(b int, ofType bool) Selector {
  	return func(n *html.Node) bool {
  		if n.Type != html.ElementNode {
  			return false
  		}
  
  		parent := n.Parent
  		if parent == nil {
  			return false
  		}
  
  		if parent.Type == html.DocumentNode {
  			return false
  		}
  
  		count := 0
  		for c := parent.LastChild; c != nil; c = c.PrevSibling {
  			if c.Type != html.ElementNode || (ofType && c.Data != n.Data) {
  				continue
  			}
  			count++
  			if c == n {
  				return count == b
  			}
  			if count >= b {
  				return false
  			}
  		}
  		return false
  	}
  }
docs: // simpleNthLastChildSelector returns a selector that implements
  // :nth-last-child(b). If ofType is true, implements :nth-last-of-type
  // instead.