We have a CI setup for running diffrent test repos, each repo has it's own requirements.txt
we build a virtualenv on each run and use that to run the tests.

our build mechines has old virtualenv, which install old version of setuptools to begin with.
once we do
pip install -r requirements.txt -U

it's brings in lots of packages that some of them are depnded on setuptool for the installtion (i.e. selenium)
cause now setuptool is depnded on six, it's not available in the same pip install, hence failing the installation.

currentlly we'll pin to older version of setuptools

I'm trying to update with a Dockerfile that will demonstrate the problem