NameError: '__builtin__'未定义，安装SQLAlchemy时出错

Question

我在我的Windows XP电脑上安装了Python 2.7.2。

最近，我使用'python setup.py install'安装了SQLAlchemy 0.7.1。在安装过程中，我遇到了以下错误信息：

byte-compiling C:\Python27\Lib\site-packages\sqlalchemy\sql\visitors.py to visitors.pyc
SyntaxError: ('invalid syntax', ('C:\\Python27\\Lib\\site-packages\\sqlalchemy\\sql\\visitors.py', 66, 34, 'class Visitable(object, metaclass=VisitableType):\n'))

当我尝试import sqlalchemy时，出现了以下错误信息：

>>> import sqlalchemy
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\site-packages\sqlalchemy\__init__.py", line 12, in <module>
  from sqlalchemy.sql import (
File "C:\Python27\lib\site-packages\sqlalchemy\sql\__init__.py", line 7, in <module>
from sqlalchemy.sql.expression import (
File "C:\Python27\lib\site-packages\sqlalchemy\sql\expression.py", line 32, in <module>
from sqlalchemy import util, exc
File "C:\Python27\lib\site-packages\sqlalchemy\util\__init__.py", line 7, in <module>
from .compat import callable, cmp, reduce, defaultdict, py25_dict, \
File "C:\Python27\lib\site-packages\sqlalchemy\util\compat.py", line 93, in <module>
callable = __builtin__.callable
NameError: name '__builtin__' is not defined

其他脚本运行得很好，__builtin__里的所有功能似乎都可以用。

我在谷歌上和SQLAlchemy的文档里找不到类似问题的例子。

这是怎么回事呢？

更新：

在compat.py里取消注释import __builtin__后，第一个问题解决了。现在我似乎在处理visitors.py时又遇到了问题：

>>> import sqlalchemy
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\site-packages\sqlalchemy\__init__.py", line 12, in <module>
from sqlalchemy.sql import (
File "C:\Python27\lib\site-packages\sqlalchemy\sql\__init__.py", line 7, in <module>
from sqlalchemy.sql.expression import (
File "C:\Python27\lib\site-packages\sqlalchemy\sql\expression.py", line 35, in <module>
from sqlalchemy.sql.visitors import Visitable, cloned_traverse
File "C:\Python27\lib\site-packages\sqlalchemy\sql\visitors.py", line 66
class Visitable(object, metaclass=VisitableType):
                                 ^
SyntaxError: invalid syntax

Answer 1

问题部分解决了：当我把SQLAlchemy版本降回到0.6.8时，一切开始正常工作。可能是0.7.1版本在Windows和2.6上有问题？