我希望能够，给定数据存储中模型的密钥，只需设置引用属性而不加载模型本身（因为我不需要该信息）。
例如：
class Book(db.Model):
author = db.StringProperty()
title = db.StringProperty()
class Review(db.Model):
book = db.ReferenceProperty(Book)
description = db.StringProperty()
假设我已经有了一个Book（调用它bookKey）的密钥，但我没有相应的Book对象本身，有没有办法做相当于
review = Review()
review.description = "It was ok, but I would recommend it for insomniacs."
review.book = bookKey
还是我需要
book = Book.get(bookKey) #I don't want this datastore access
#as I don't need the book object.
review = Review()
review.description = "It was ok, but I would recommend it for insomniacs."
review.book = book
我找到了从ReferencePropertyusing中提取密钥和 ID 的方法get_value_for_datastore，但我在“设置”之后。