Django - 一对多关系中的否定查询

Given these models:

鉴于这些模型：

class Profile(models.Model):
    name = models.CharField(max_length=50)

class BlogPost(models.Model):
    name = models.CharField(max_length=50)
    created_by = models.ForeignKey(Profile, related_name='posts')

class Comment(models.Model):
    blog = models.ForeignKey(BlogPost, related_name='comments')
    body_text = models.TextField()
    created_by = models.ForeignKey(Profile, null=True, blank=True, on_delete=models.SET_NULL)
class Profile(m