<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def start(self) -> None: """Connect websocket to deCONZ."""

        if self.config:
            self.websocket = self.ws_client(
                self.loop, self.session, self.host,
                self.config.websocketport, self.async_session_handler)
            self.websocket.start()
        else:
            _LOGGER.error('No deCONZ config available')