code: def add_adapter(self, adapter):
          
  
          if self._started:
              raise InternalError("New adapters cannot be added after start() is called")
  
          if isinstance(adapter, DeviceAdapter):
              self._logger.warning("Wrapping legacy device adapter %s in async wrapper", adapter)
              adapter = AsynchronousModernWrapper(adapter, loop=self._loop)
  
          self.adapters.append(adapter)
  
          adapter_callback = functools.partial(self.handle_adapter_event,
                                               len(self.adapters) - 1)
          events = ['device_seen', 'broadcast', 'report', 'connection',
                    'disconnection', 'trace', 'progress']
  
          adapter.register_monitor([None], events, adapter_callback)
docs: Add a device adapter to this aggregating adapter.