How to use the puput.models.BlogPage.objects.get function in puput

def get_blog_page(self, slug, title):
        # Create blog page
        try:
            self.blogpage = BlogPage.objects.get(slug=slug)
        except BlogPage.DoesNotExist:
            # Get root page
            rootpage = Page.objects.first()

            # Set site root page as root site page
            site = Site.objects.first()
            site.root_page = rootpage
            site.save()

            # Get blogpage content type
            self.blogpage = BlogPage(title=title, slug=slug)
            rootpage.add_child(instance=self.blogpage)
            revision = rootpage.save_revision()
            revision.publish()