def METHOD_NAME(self, request, slug):
    serializer_context = {'request': request}
    try:
        serializer_instance = self.queryset.get(slug=slug)
    except Article.DoesNotExist:
        raise NotFound('An article with this slug does not exist.')
    serializer_data = request.data.get('article', {})
    serializer = self.serializer_class(
        serializer_instance, 
        context=serializer_context,
        data=serializer_data, 
        partial=True
    )
    serializer.is_valid(raise_exception=True)
    serializer.save()
    return Response(serializer.data, status=status.HTTP_200_OK)