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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 post_save(sender, instance, created, **kwargs):
 """ After save create order instance for sending instance for orderable models. """

    # Only create order model instances for
    # those modules specified in settings.
    model_label = '.'.join([sender._meta.app_label, sender._meta.object_name])
    labels = resolve_labels(model_label)

    order_field_names = is_orderable(model_label)
    if order_field_names:
        orderitem_set = getattr(
            instance,
            resolve_order_item_related_set_name(labels)
        )
        if not orderitem_set.all():
            fields = {}
            for order_field_name in order_field_names:
                fields[order_field_name] = 1
            orderitem_set.model.objects.create(item=instance, **fields)
            sanitize_order(orderitem_set.model)