为什么要从字符串模板创建Python的namedtuple实例？

Question

当我阅读Python的collections模块（http://hg.python.org/cpython/file/2.7/Lib/collections.py#l234）的源代码时，我发现namedtuple函数从使用exec执行的字符串模板创建类的定义。为什么不简单地在函数中定义一个类，就像在编写装饰器时那样？在我看来，这将是一个更具可读性和更可靠的解决方案，不是吗？我敢打赌Python核心开发人员知道他们在做什么，那么我在这里遗漏了什么呢？你知道吗

Answer 1

雷蒙德·赫廷格在他的original ActiveState recipe中简短地提到了这一点：

Thanks to Peter Kovac pointing-out deficiencies in the keyword argument checking. Because of his comments, the recipe has evolved to its current exec-style where we get all of Python's high-speed builtin argument checking for free. The new style of building and exec-ing a template made both the __new__ and __repr__ functions faster and cleaner than in previous versions of this recipe.