old_contents: from rest_framework import viewsets, permissions, filters as rf_filters
  
  from nodeconductor.structure import filters as structure_filters
  
  from . import filters, models, serializers
  
  
  class InvoiceViewSet(viewsets.ReadOnlyModelViewSet):
      queryset = models.Invoice.objects.all()
      serializer_class = serializers.InvoiceSerializer
      lookup_field = 'uuid'
      permission_classes = (permissions.IsAuthenticated, permissions.DjangoObjectPermissions)
      filter_backends = (structure_filters.GenericRoleFilter, rf_filters.DjangoFilterBackend,)
      filter_class = filters.InvoiceFilter
  
new_contents: from rest_framework import viewsets, permissions, filters as rf_filters
  
  from nodeconductor.structure import filters as structure_filters
  
  from . import filters, models, serializers
  
  
  class InvoiceViewSet(viewsets.ReadOnlyModelViewSet):
      queryset = models.Invoice.objects.order_by('-year', '-month')
      serializer_class = serializers.InvoiceSerializer
      lookup_field = 'uuid'
      permission_classes = (permissions.IsAuthenticated, permissions.DjangoObjectPermissions)
      filter_backends = (structure_filters.GenericRoleFilter, rf_filters.DjangoFilterBackend,)
      filter_class = filters.InvoiceFilter
  
subject: Order invoices by default