code: def node_contents_str(tag):
      
      if not tag:
          return None
      tag_string = ''
      for child_tag in tag.children:
          if isinstance(child_tag, Comment):
              # BeautifulSoup does not preserve comment tags, add them back
              tag_string += '<!--%s-->' % unicode_value(child_tag)
          else:
              tag_string += unicode_value(child_tag)
      return tag_string if tag_string != '' else None
docs: Return the contents of a tag, including it's children, as a string.
      Does not include the root/parent of the tag.