安装Python包：缺少目录

Question

我目前正在尝试安装一些python包，但似乎不明白为什么它不能工作。运行ez_install时出现以下错误：

$ easy_install scipy
error: can't create or remove files in install directory

The following error occurred while trying to add or remove files in the installation directory:

[Errno 2] No such file or directory: '/Users/blackbird/Library/Python/2.7/site-packages/test-easy-install-5544.write-test'

The installation directory you specified (via --install-dir, --prefix, or the distutils default setting) was:

/Users/blackbird/Library/Python/2.7/site-packages/

This directory does not currently exist.  Please create it and try again, or choose a different installation directory (using the -d or --install-dir option).

我已经进入了我的库，Python文件夹不存在。显然，我可以手动创建它，但这是否表明我做错了什么，或者我遗漏了什么？在