code: def start(self):
          
          if self.huey.immediate:
              raise ConfigurationError(
                  'Consumer cannot be run with Huey instances where immediate '
                  'is enabled. Please check your configuration and ensure that '
                  '"huey.immediate = False".')
          # Log startup message.
          self._logger.info('Huey consumer started with %s %s, PID %s at %s',
                            self.workers, self.worker_type, os.getpid(),
                            self.huey._get_timestamp())
          self._logger.info('Scheduler runs every %s second(s).',
                            self.scheduler_interval)
          self._logger.info('Periodic tasks are %s.',
                            'enabled' if self.periodic else 'disabled')
  
          self._set_signal_handlers()
  
          msg = ['The following commands are available:']
          for command in self.huey._registry._registry:
              msg.append('+ %s' % command)
  
          self._logger.info('\n'.join(msg))
  
          # We'll temporarily ignore SIGINT and SIGHUP (so that it is inherited
          # by the child-processes). Once the child processes are created, we
          # restore the handler.
          original_sigint_handler = signal.signal(signal.SIGINT, signal.SIG_IGN)
          if hasattr(signal, 'SIGHUP'):
              original_sighup_handler = signal.signal(signal.SIGHUP, signal.SIG_IGN)
  
          self.scheduler.start()
          for _, worker_process in self.worker_threads:
              worker_process.start()
  
          signal.signal(signal.SIGINT, original_sigint_handler)
          if hasattr(signal, 'SIGHUP'):
              signal.signal(signal.SIGHUP, original_sighup_handler)
docs: Start all consumer processes and register signal handlers.