book_children = book.children.all().order_by('parent_number')
extra_where = 'catalogue_tag.category = "theme"'
book_themes = models.Tag.objects.related_for_model(book_tag, models.Fragment, counts=True, extra={'where': [extra_where]})
book_children = book.children.all().order_by('parent_number')
extra_where = 'catalogue_tag.category = "theme"'
book_themes = models.Tag.objects.related_for_model(book_tag, models.Fragment, counts=True, extra={'where': [extra_where]})