code: def handle_startendtag(self, tag, attrs):
          
          is_foreign = tag not in _VOID_ELEMENTS
          self._append_tag(tag, attrs, closing=is_foreign)
          if tag in _BLOCK_ELEMENTS:
              self._enter_newline()
          elif tag not in _HIDDEN_ELEMENTS:
              self._reset_newline_status()
docs: Normalize the tag with trailing '/' character (such as `<img ... />`).
  
          The trailing '/' character has no effect on void elements, but on
          foreign elements it marks the start tag as self-closing.
  
          .. seealso::
             `HTML5 - Start tags
              <http://www.w3.org/TR/html5-author/syntax.html#syntax-start-tag>`_