def get_product_variant(self, extra):
        msg = "Method get_product_variant(extra) must be implemented by subclass: `{}`"
        raise NotImplementedError(msg.format(self.__class__.__name__))
Downloads the files associated with a particular app version.
dataset/ETHPy150Open awesto/django-shop/example/myshop/models/polymorphic/product.py/Product.get_product_variant--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/tools/appcfg.py/DoDownloadApp