def clear_uuids(apps, schema_editor):
 Document = apps.get_model(u'wiki', u'Document')
 Document.objects.exclude(uuid__isnull=True).update(uuid=None)

def clear_uuids ( apps , schema_editor ) : Document = apps . get_model ( u'wiki' , u'Document' ) Document . objects . exclude ( uuid__isnull = True ) . update ( uuid = None )
clear document .