By default, when in the __main__ module, __builtins__ is the built-in module __builtin__ (note: no ‘s’); when in any other module, __builtins__ is an alias for the dictionary of the __builtin__ module itself.
既然是这样,那么一个__builtin__不就已经足够了吗?何必多此一举添加一个__builtins__呢?那么__builtins__存在的意义是什么呢?
ps:python2.7