code: def clean_devices(self, config_file, region=None, profile_name=None):
          
          config = GroupConfigFile(config_file=config_file)
          if region is None:
              region = self._region
  
          devices = config['devices']
          if 'device_thing_name' in devices:
              logging.info('Configured devices already clean')
              return
  
          policy_name = config['misc']['policy_name']
          for device in devices:
              cert_arn = devices[device]['cert_arn']
              cert_id = devices[device]['cert_id']
              thing_name = device
              logging.info('Deleting device_thing_name:{0}'.format(thing_name))
              GroupCommands._delete_thing(
                  cert_arn, cert_id, thing_name, region, policy_name, profile_name
              )
          config.make_devices_fresh()
docs: Clean all device related provisioned artifacts from both the local file
          and the AWS Greengrass service.
  
          :param config_file: config file containing the devices to clean
          :param region: the region in which the devices should be cleaned.
              [default: us-west-2]
          :param profile_name: the name of the `awscli` profile to use.
              [default: None]