title: QuerySet, Object has no attribute id - Django
body: <p>I'm trying to fetch the id of certain object in django but I keep getting the following error
  Exception Value: QuerySet; Object has no attribute id.
  my function in views.py</p>
  
  <pre><code>@csrf_exempt  
  def check_question_answered(request):
      userID = request.POST['userID']
      markerID = request.POST['markerID']
      title=request.POST['question']
      m = Marker.objects.get(id=markerID)
      u = App_User.objects.get(id=userID) 
      print userID
      print markerID
      print title
      # userID='1'
      # markerID='1'
      # title='Hello'
      at = AttachedInfo.objects.filter(attachedMarker=m.id, title=title)
      print 'user'
      print u.id
      print 'marker'
      print m.id
      print 'att'
      print at
      #print at.id
      if(Answer.objects.filter(marker=m.id, user=u.id, attachedInfo=at.id)):
          print 'pass'
          return HttpResponse('already answered')
      else:
          print 'not'
          return HttpResponse('not answered yet') 
  </code></pre>
  
  <p>The error occurs in the if condition  in this part (attachedInfo=at.id). I checked that as when I removed it from the condition, everything was working fine.</p>
  
  <p>Here's models.py</p>
  
  <pre><code>class AttachedInfo(models.Model):
      title = models.CharField(max_length=200)
      helpText = models.CharField(max_length=200, null=True, blank=True)
      type = models.CharField(max_length=200)
      attachedMarker = models.ForeignKey(Marker)
      answer1 = models.CharField(max_length=200, null=True, blank=True)
      answer2 = models.CharField(max_length=200, null=True, blank=True)
      answer3 = models.CharField(max_length=200, null=True, blank=True)
      answer4 = models.CharField(max_length=200, null=True, blank=True)
      correctAnswer = models.CharField(max_length=50, null=True, blank=True)
      optionalMessage = models.CharField(max_length=200, null=True, blank=True)
      def __unicode__(self):
          return self.title
  
  class Answer(models.Model):
      user = models.ForeignKey(App_User)
      app = models.ForeignKey(App, null=True, blank=True)
      marker = models.ForeignKey(Marker)
      attachedInfo = models.ForeignKey(AttachedInfo)
      textAnswer = models.CharField(max_length=200, null=True, blank=True)
      mcqAnswer = models.CharField(max_length=200, null=True, blank=True)
      answered = models.BooleanField(default=False)
      def __unicode__(self):
          return self.attachedInfo.title
  </code></pre>
  
  <p>Any help why I'm getting this error?!</p>