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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def do_pending_lookups(event, sender, **kwargs):

 """Handle any pending relations to the sending model.
 Sent from class_prepared."""

    key = (sender._meta.app_label, sender._meta.name)
    for callback in pending_lookups.pop(key, []):
        callback(sender)