title: How to properly remove a specific ManyToMany relationship?
body: <p>I have a ManyToMany relationship with one of my Models.  On deleting a child, I want to remove the relationship but leave the record as it might be being used by other objects.  On calling the delete view, I get an AttributeError error:</p>
  
  <blockquote>
    <p>Exception Value: 'QuerySet' object has
    no attribute 'clear'</p>
  </blockquote>
  
  <p>This is my models.py:</p>
  
  <pre><code>class Feed(models.Model):
      username = models.CharField(max_length=255, unique=True)
  
  class Digest(models.Model):
      name = models.CharField(max_length=255)
      user = models.ForeignKey(User)
      items = models.PositiveIntegerField()
      keywords = models.CharField(max_length=255, null=True, blank=True)
      digest_id = models.CharField(max_length=20, unique=True)
      time_added = models.DateTimeField(auto_now_add=True)
      active = models.BooleanField(default=1)
      feeds = models.ManyToManyField(Feed)
  </code></pre>
  
  <p>And the relevant section of views.py:</p>
  
  <pre><code>def feed_delete(request, id):
      digest = get_object_or_404(Digest, id=id)
      if digest.user == request.user:
          Feed.objects.get(id=request.POST.get('id')).digest_set.filter(id=id).clear()
  
      return HttpResponseRedirect(digest.get_absolute_url())
  </code></pre>