小编Dan*_*737的帖子

我在Windows 7上.我安装了Python 2.7多年.我最近安装了Python 3.4.我正在尝试使用新的py启动器.当我打开cmd终端并输入时py -2,我收到以下错误消息:Requested Python version (2) not installed.如何让py知道我的python 2.7安装？

注意:如果出现问题,python 2.7安装在非标准目录(不在C:\ Python27中)中.

我想测试以下代码

import weakref

class WeakBoundMethod:
    """
    Wrapper around a method bound to a class instance. As opposed to bare
    bound methods, it holds only a weak reference to the `self` object,
    allowing it to be deleted.

    This can be useful when implementing certain kinds of systems that
    manage callback functions, such as an event manager.

    """
    def __init__(self, meth):
        """
        Initializes the class instance. It should be ensured that methods
        passed through the `meth` parameter are always bound methods. Static …