code: func writeNodeText(n *html.Node, b *bytes.Buffer) {
  	switch n.Type {
  	case html.TextNode:
  		b.WriteString(n.Data)
  	case html.ElementNode:
  		for c := n.FirstChild; c != nil; c = c.NextSibling {
  			writeNodeText(c, b)
  		}
  	}
  }
docs: // writeNodeText writes the text contained in n and its descendants to b.