old_contents: from django.core.management import BaseCommand, CommandError
  
  from channels import DEFAULT_CHANNEL_LAYER
  from channels.layers import get_channel_layer
  from channels.log import setup_logger
  from channels.routing import get_default_application
  from channels.worker import Worker
  
  
  class Command(BaseCommand):
  
      leave_locale_alone = True
  
      def add_arguments(self, parser):
          super(Command, self).add_arguments(parser)
          parser.add_argument(
              "--layer", action="store", dest="layer", default=DEFAULT_CHANNEL_LAYER,
              help="Channel layer alias to use, if not the default.",
          )
          parser.add_argument(
              "channels",
              nargs="+",
              help="Channels to listen on."
          )
  
      def handle(self, *args, **options):
          # Get the backend to use
          self.verbosity = options.get("verbosity", 1)
          # Get the channel layer they asked for (or see if one isn't configured)
          if "layer" in options:
              self.channel_layer = get_channel_layer(options["layer"])
          else:
              self.channel_layer = get_channel_layer()
          if self.channel_layer is None:
              raise CommandError("You do not have any CHANNEL_LAYERS configured.")
          # Run the worker
          self.logger = setup_logger("django.channels", self.verbosity)
          self.logger.info("Running worker for channels %s", options["channels"])
          worker = Worker(
              application=get_default_application(),
              channels=options["channels"],
              channel_layer=self.channel_layer,
          )
          worker.run()
  
new_contents: from django.core.management import BaseCommand, CommandError
  
  from channels import DEFAULT_CHANNEL_LAYER
  from channels.layers import get_channel_layer
  from channels.log import setup_logger
  from channels.routing import get_default_application
  from channels.worker import Worker
  
  
  class Command(BaseCommand):
  
      leave_locale_alone = True
      worker_class = Worker
  
      def add_arguments(self, parser):
          super(Command, self).add_arguments(parser)
          parser.add_argument(
              "--layer", action="store", dest="layer", default=DEFAULT_CHANNEL_LAYER,
              help="Channel layer alias to use, if not the default.",
          )
          parser.add_argument(
              "channels",
              nargs="+",
              help="Channels to listen on."
          )
  
      def handle(self, *args, **options):
          # Get the backend to use
          self.verbosity = options.get("verbosity", 1)
          # Get the channel layer they asked for (or see if one isn't configured)
          if "layer" in options:
              self.channel_layer = get_channel_layer(options["layer"])
          else:
              self.channel_layer = get_channel_layer()
          if self.channel_layer is None:
              raise CommandError("You do not have any CHANNEL_LAYERS configured.")
          # Run the worker
          self.logger = setup_logger("django.channels", self.verbosity)
          self.logger.info("Running worker for channels %s", options["channels"])
          worker = self.worker_class(
              application=get_default_application(),
              channels=options["channels"],
              channel_layer=self.channel_layer,
          )
          worker.run()
  
subject: Allow subclasses to customise the worker class