在Python中自动下载所需模块的最简单方法？

I would like to release a python module I wrote which depends on several packages. What's the easiest way to make it so these packages are programmatically downloaded just in case they are not available on the system that's being run? Most of these modules should be available by easy_install or pip or something like that. I simply want to avoid having the user install each module separately.I would like to release a python module I wrote