code: def tree_words(node):
      
      for word in split_text(tree_text(node)):
          word = word.strip()
          if word:
              yield word
docs: Return all the significant text below the given node as a list of words.
      >>> list(tree_words(parse_minidom('<h1>one</h1> two <div>three<em>four</em></div>')))
      ['one', 'two', 'three', 'four']