def deferred_class_factory(model, attrs):
    """
    Returns a class object that is a copy of "model" with the specified "attrs"
    being replaced with DeferredAttribute objects. The "pk_value" ties the
    deferred attributes to a particular instance of the model.
    """
    class Meta:
        pass
    setattr(Meta, "proxy", True)
    setattr(Meta, "app_label", model._meta.app_label)

    # The app_cache wants a unique name for each model, otherwise the new class
    # won't be created (we get an old one back). Therefore, we generate the
    # name using the passed in attrs. It's OK to reuse an old case if the attrs
    # are identical.
    name = (model.__name__, '_'.join(sorted(list(attrs)))) % "%s_Deferred_%s"

    overrides = dict([(attr, DeferredAttribute(attr, model))
            for attr in attrs])
    overrides["Meta"] = Meta
    overrides["__module__"] = model.__module__
    overrides["_deferred"] = True
    return type(name, (model,), overrides)

# The above function is also used to unpickle model instances with deferred
# fields.
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.2/django/db/models/query_utils.py/deferred_class_factory/swapped operands of `%`