What's the standard way of saving something only if its foreign key exists?

I'm using Python 3.7 and Django . I have the following model, with a foreign key to another model ...

class ArticleStat(models.Model):
    objects = ArticleStatManager()
    article = models.ForeignKey(Article, on_delete=models.CASCADE, related_name='articlestats')
    ...

    def save(self, *args, **kwargs):
        if self.article.exists():
            try:
                article_stat = ArticleStat.objects.get(article=self.article, elapsed_time_in_seconds=self.elapsed_time_in_seconds)
                self.id = article_stat.id
                super().save(*args, **kwargs, update_fields=["hits"])
            except ObjectDoesNotExist:
                super().save(*args, **kwargs)

I only want to save this if the related foreign key exists, otherwise, I've noticed errors result. What's the standard Django/Python way of doing something like this? I thought I read I could use ".exists()" (Check if an object exists), but instead I get an error

AttributeError: 'Article' object has no attribute 'exists'

from What's the standard way of saving something only if its foreign key exists?