title: Django: Access given field's choices tuple
body: <p>I would like to get the named values of a choices field for a choice that is not currently selected. Is this possible?</p>
  
  <p>For instance: models.py</p>
  
  <pre><code>FILE_STATUS_CHOICES = (
      ('P', 'Pending'),
      ('A', 'Approved'),
      ('R', 'Rejected'),
  )
  
  class File(models.Model):
      status = models.CharField(max_length=1, default='P', choices=FILE_STATUS_CHOICES)
  </code></pre>
  
  <p>views.py</p>
  
  <pre><code>f = File()
  f.status = 'P'
  f.save()
  
  old_value = f.status
  
  print f.get_status_display()
  &gt; Pending
  
  f.status = 'A'
  f.save()
  
  new_value = f.status
  
  print f.get_status_display()
  &gt; Approved
  </code></pre>
  
  <p>How can I get the old display value from the 'P' to 'Pending?' I may be able to do so by creating a form in the view and accessing its dictionary of values/labels. Is this the best/only approach?</p>