title: What parameters does Django's models.DO_NOTHING expect?
body: <p>I've searched <a href="https://docs.djangoproject.com/en/1.9/ref/models/fields/#django.db.models.ForeignKey.on_delete" rel="noreferrer">the documentation</a> but I haven't found any explanation of the parameters. </p>
  
  <p>The implementation of the <code>DO_NOTHING</code> does exactly that, so it shouldn't matter what I'm passing in, but for other methods (such as <a href="https://docs.djangoproject.com/en/1.9/ref/models/fields/#django.db.models.CASCADE" rel="noreferrer">CASCADE</a>) they're actually used.</p>
  
  <p>The closest explanation I've found is <a href="https://stackoverflow.com/questions/8543877/django-models-foreignkey-on-delete-attribute-does-it-really-delete-all-related">a discussion</a> of CASCADE.</p>
  
  <p>What datatypes are <code>collector</code>, <code>field</code>, <code>sub_objs</code>, and <code>using</code>, and what values do I pass?</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>I'm using it in my model, like so:</p>
  
  <pre><code>class Office(models.Model):
  
      #   Office locations have a name, and a location.
  
      display_name = models.CharField(max_length=255)
  
      location = models.OneToOneField(
          GeoLocation,
          on_delete=models.DO_NOTHING(None, None, None, None)
      )
  </code></pre>