title: django was_published_recently error
body: <p>In tutorial <a href="https://docs.djangoproject.com/en/1.4/intro/tutorial02/" rel="nofollow">here</a> I get down to where you run was_published_recently and I get this error:</p>
  
  <blockquote>
    <p>ImproperlyConfigured at /admin/polls/poll/
    PollAdmin.list_display[2], 'was_published_recently' is not a callable or an attribute of 'PollAdmin' or found in the model 'Poll'.
    Request Method: GET
    Request URL:    /admin/polls/poll/
    Django Version: 1.4
    Exception Type: ImproperlyConfigured
    Exception Value:<br>
    PollAdmin.list_display[2], 'was_published_recently' is not a callable or an attribute of 'PollAdmin' or found in the model 'Poll'.
    Exception Location: C:\Python27\lib\site-packages\django\contrib\admin\validation.py in validate, line 38</p>
  </blockquote>
  
  <p>here is my code:</p>
  
  <pre><code>from polls.models import Poll
  
  from django.contrib import admin
  
  from polls.models import Choice
  
  class ChoiceInline(admin.TabularInline):
    model = Choice
    extra = 3
  
  class PollAdmin(admin.ModelAdmin):
  
     fieldsets = [
      (None,               {'fields': ['question']}),
      ('Date information', {'fields': ['pub_date'], 'classes': ['collapse']}),
      ]
     inlines = [ChoiceInline]
  
  class PollAdmin(admin.ModelAdmin):
     # ...
     list_display = ('question', 'pub_date', 'was_published_recently')
  
    admin.site.register(Poll, PollAdmin)
  </code></pre>
  
  <p>here is my poll model</p>
  
  <pre><code>  from django.db import models
  
    class Poll(models.Model):
     question = models.CharField(max_length=200)
     pub_date = models.DateTimeField('date published')
  
  
    class Choice(models.Model):
     poll = models.ForeignKey(Poll)
     choice = models.CharField(max_length=200)
     votes = models.IntegerField()
  
    class Poll(models.Model):
     # ...
     def __unicode__(self):
      return self.question
  
    class Choice(models.Model):
      # ...
      def __unicode__(self):
      return self.choice
  </code></pre>