code: def readProtocolVersion(self, data):
          
          data.readType(self._version)
          if not self._version.value in [ProtocolVersion.RFB003003, ProtocolVersion.RFB003007, ProtocolVersion.RFB003008]:
              self._version.value = ProtocolVersion.UNKNOWN
docs: Read protocol version
          @param data: Stream may contain protocol version string (ProtocolVersion)