code: def _read_ip_hextet(self):
          
          _htet = self._read_fileng(4).hex()
          _vers = _htet[0]                    # version number (6)
          _tcls = int(_htet[0:2], base=16)    # traffic class
          _flow = int(_htet[2:], base=16)     # flow label
  
          return (_vers, _tcls, _flow)
docs: Read first four hextets of IPv6.