document children wtf?

gistfile1.txt

(Pdb) p Document.objects.get(slug='parent')
<Document: [en-US] parent>
(Pdb) p Document.objects.get(slug='child')
<Document: [en-US] child>
(Pdb) p Document.objects.get(slug='child').parent
<Document: [en-US] parent>
(Pdb) p (Document.objects.get(slug='parent') == Document.objects.get(slug='child').parent)
True
(Pdb) p Document.objects.get(slug='parent').children
<django.db.models.fields.related.RelatedManager object at 0xa4d4eac>
(Pdb) p Document.objects.get(slug='parent').children.count()
0
(Pdb) p Document.objects.get(slug='parent').id
1L
(Pdb) p Document.objects.get(slug='child').id
2L

children is this: https://github.com/mozilla/kuma/blob/master/apps/wiki/models.py#L564