Comment by zahlman

I got confused by the direction of the discussion.

My original point was that Requests imports in pip used to not be deferred like that, so you would pay for them up front, even if they turned out to be irrelevant. (But also they are relevant more often than they should be, i.e. the deferral system doesn't work as well as it should.)

Part of the reason you pay for them is to run top-level code (to create function and class objects) that are irrelevant to what the program is actually doing. But another big part is the cost of actually locating the files, reading them, and deserializing bytecode from them. This happens at import time even if you don't invoke any of the functionality.