def _read_flow_control(self, first_byte, control_block):
        reserved = first_byte & 0x1f
        if reserved != 0:
            raise PhysicalConnectionError(
                _DROP_CODE_INVALID_MUX_CONTROL_BLOCK,
                'Reserved bits must be unset')

        try:
            control_block.channel_id = self.read_channel_id()
            control_block.send_quota = self._read_number()
        except __HOLE__, e:
            raise PhysicalConnectionError(_DROP_CODE_INVALID_MUX_CONTROL_BLOCK,
                                          str(e))

        return control_block
dataset/ETHPy150Open google/pywebsocket/mod_pywebsocket/mux.py/_MuxFramePayloadParser._read_flow_control