Description

pip install scikit-learn fails on python 2

Steps/Code to Reproduce

pip install scikit-learn in a python 2 environment

Expected Results

install succeeds

Actual Results

RuntimeError: Scikit-learn requires Python 3.5 or later. The current Python version is 2.7.16rc1 installed in...

Versions

I expect a lower version to be installed since 0.21 is marked as python 3 only. However the command results in an attempt to install 0.21 and then failure.