          pass
  
      @action(detail=False, url_name='list-custom')
      def custom_list_action(self, request, *args, **kwargs):
          pass
  
      @action(detail=True)
      def detail_action(self, request, *args, **kwargs):
          pass
  
 
</s> remove         pass
 </s> add         raise NotImplementedError()  # pragma: no cover </s> remove         pass
 </s> add         raise NotImplementedError()  # pragma: no cover </s> remove         pass
 </s> add         raise NotImplementedError()  # pragma: no cover </s> remove         pass
 </s> add         raise NotImplementedError()  # pragma: no cover </s> remove         pass
 </s> add         raise NotImplementedError()  # pragma: no cover
        raise NotImplementedError()  # pragma: no cover
          pass
  
      @action(detail=False, url_name='list-custom')
      def custom_list_action(self, request, *args, **kwargs):
        raise NotImplementedError()  # pragma: no cover
  
      @action(detail=True)
      def detail_action(self, request, *args, **kwargs):
          pass
  
keep keep keep keep replace keep keep keep keep keep
 tests: remove some dead code, use `assert 0` for never called methods (#5973)

* tests: remove some dead code, use `assert 0` for never called methods

* fixup! tests: remove some dead code, use `assert 0` for never called methods 
tests/test_viewsets.py