def do_pending_lookups(sender, **kwargs):
    key = (sender._meta.app_label, sender.__name__)
    for cls, field, operation in pending_lookups.pop(key, []):
        operation(field, sender, cls)
Handle any pending relations to the sending model. Sent from class_prepared.
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/Django-1.6.10/django/db/models/fields/related.py/do_pending_lookups