code: def _extract_tag_from_data(self, data, tag_name=b'packet'):
          
          opening_tag = b'<' + tag_name + b'>'
          closing_tag = opening_tag.replace(b'<', b'</')
          tag_end = data.find(closing_tag)
          if tag_end != -1:
              tag_end += len(closing_tag)
              tag_start = data.find(opening_tag)
              return data[tag_start:tag_end], data[tag_end:]
          return None, data
docs: Gets data containing a (part of) tshark xml.
  
          If the given tag is found in it, returns the tag data and the remaining data.
          Otherwise returns None and the same data.
  
          :param data: string of a partial tshark xml.
          :return: a tuple of (tag, data). tag will be None if none is found.