pip9 dependency failure: tornado + sprockets.http

[dave-shawley]

This fails because sprockets.http pins tornado to a version earlier than the generally available version. This will fail without specifying any version or explicitly with pip install tornado==5.0 sprockets.http==1.5.0.

% pip uninstall -qy tornado sprockets.http
% pip install tornado sprockets.http
Collecting tornado
  Using cached tornado-5.0.tar.gz
Collecting sprockets.http
  Using cached sprockets.http-1.5.0-py2.py3-none-any.whl
Installing collected packages: tornado, sprockets.http
  Running setup.py install for tornado ... done
Successfully installed sprockets.http-1.5.0 tornado-5.0
% pip check
sprockets.http 1.5.0 has requirement tornado<5,>=3.1, but you have tornado 5.0.