Using virtualenv with -p python2
While installing pip install gluoncv it errors out with following error
Requirement already satisfied: setuptools in ./mxv16_p2/lib/python2.7/site-packages (45.0.0)
ERROR: Package 'setuptools' requires a different Python: 2.7.12 not in '>=3.5'
Thanks to https://github.com/pypa/virtualenv/issues/1493
Specifically this comment : https://github.com/pypa/virtualenv/issues/1493#issuecomment-576250710
pip install --upgrade 'setuptools<45.0.0'
It expected a lower version of setuptools and hence pip install --upgrade to lower version [i.e. downgraded]