I have an idea for a new special method in a class called __first__(). The main purpose of it would be to setup somethings a class needs to run before it is first initiated, probably only really in modules because in your code you could simply put this setup stuff before the class however if you are calling something like 'from foo import Bar', where Bar is a class and Bar needs some specific imports you would need something to run the first time Bar is initiated.
I have two possible ideas for how this could be done. To look at how this is going to work I will make an example class which would be in the class foo:
class Bar(object):
    def __first__():
        import math
    def __init__(self, n):
        self.a = math.log(2, n)

The first possible way is that if you just call Bar (without brackets or any attributes) this is when it will run __first__ so you can just do this after you run 'from foo import Bar'. However I don't particularly like this idea because you could just create a staticmethod setup or something instead of __first__ and then rather than running Bar you would just run Bar.setup(), not much harder.
Personally I prefer my second idea. This is that when you first run Bar.__new__() it will check if it has a __first__() and if so it will run __first__ and then it will run the normal __new__. However, if you then create another instance, so run __new__ again, it will not run __first__ again so it is still an efficient place to run imports or setup of things.

As an example of where this could be useful, I made a module 'temperature' to help me neatly read one-wire temperature sensors with a raspberry pi. This included a class Sensor which you gave the code of the sensor and then when you called temp of that instance it will return what temperature that sensor is reading. I would like in my other code to be able to run 'from temperature import Sensor' because that would then mean I could just call Sensor('28-000648372f') to create a sensor however at the start of this module it imports os and glob and it also runs some setup for how it reads the sensors and has such I have to just do 'import temperature' and then every time I create a sensor I have to call temperature.Sensor which isn't as nice.

I was wondering what you thought of this idea.