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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def published(self, request=None):
 """ Returns the published documents in the current language. :param request: A Request instance. """

        language = getattr(request, 'LANGUAGE_CODE', get_language())
        if not language:
            return self.model.objects.none()

        qs = self.get_queryset()
        qs = qs.filter(
            translations__is_published=True,
            translations__language_code=language,
        )
        # either it has no category or the one it has is published
        qs = qs.filter(
            models.Q(category__isnull=True) |
            models.Q(category__is_published=True))
        return qs