code: def isEndTagTo(self, opener):
          
          if not (self._isendtag and opener.isOpeningTag()):
              return False
  
          return self._tagname.lower() == opener.getTagName().lower()
docs: Args:
              opener (obj): :class:`HTMLElement` instance.
  
          Returns:
              bool: True, if this element is endtag to `opener`.