async def create(self, name, slaves):
        """Create a group."""
        # NOTE: codectype and codecbitrate were simply chosen from an example..
        res = await self.call("X_Start", GroupMode="GROUP",
                              GroupName=name,
                              SlaveList=",".join(slaves),
                              CodecType=0x0040,
                              CodecBitrate=0x0003)
        return res