text: from rest_framework import mixins, viewsets
  from rest_framework.settings import api_settings
  
  
  class UserViewSet(mixins.RetrieveModelMixin,
                    mixins.UpdateModelMixin,
                    mixins.ListModelMixin,
                    viewsets.GenericViewSet):
      """
      """
      queryset = None
      serializer_class = None
  
      lookup_field = 'pk'
  
      # The filter backend classes to use for queryset filtering
      filter_backends = api_settings.DEFAULT_FILTER_BACKENDS
  
      # The style to use for queryset pagination.
      authentication_classes = api_settings.DEFAULT_AUTHENTICATION_CLASSES
  
      permission_classes = api_settings.DEFAULT_PERMISSION_CLASSES
  