TIL: A Python module from which you can import anything

What is a TIL?

Today I learnt how to make a Python module from which you can import anything.

Yuvi asked if you can write a Python module that will allow anything to be imported from it. A bit like from idealmock import whatever, does_not_exist.

I thought "how hard can it be?" and off I went to find out.

The answer is that it is not very hard to do. I first read about the import machinery of Python, learnt a bit about importlib and in the end the solution had nothing to do with all that.

It is surprisingly simple:

def __getattr__(name):

If you put this code in your module, say blackhole.py you can import anything you want from it: from blackhole import something, does_not_exist or you can import the whole module and then access anything you want: import blackhole; blackhole.something.

It is pretty neat.

If you want to learn more about module level __getattr__ and some real world use cases checkout PEP 562 -- Module __getattr__ and __dir__ which has a nice trick for dealing with deprecated functions in it.

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