text: from datetime import timedelta
  from django.core.management.base import BaseCommand
  from django.conf import settings
  from django.db.models import Q
  from django.utils.timezone import now
  from apps.questionnaire.models import Lock
  
  
  class Command(BaseCommand):
      """
      Purge stale locks.
      """
      def handle(self, **options):
          expired = now() - timedelta(minutes=settings.QUESTIONNAIRE_LOCK_TIME)
          Lock.objects.filter(
              Q(is_finished=True) | Q(start__lte=expired)
          ).delete()
  