How to filter by not empty string in a Django Rest Framework request querysting?

As per title, given a model that has a string field like:

class MyModel(models.Model):
    name = models.CharField(null=True, blank=True, max_length=50)

I can configure a generic api with filters in Django Test Framework like this:

class MyModelApi(ListAPIView):
    serializer_class = MyModelSerializer
    model = MyModel    
    filterset_fields = ('name')
    filter_backends = (DjangoFilterBackend)
    querystring = MyModel.objects.all()

This allows me to filter the api like this:


I also know how to configure such api so that it is possible to use filters different from the exact one like:


What I cannot figure out is: how to get all the MyModel object whose name field is not an empty list? I've tried the following with no results: