Comment 1 for bug 1816625

Here are my pip and tox versions:

osboxes@osboxes:~/git/placement$ pip show pip tox
---
Metadata-Version: 1.1
Name: pip
Version: 8.1.1
Summary: The PyPA recommended tool for installing Python packages.
Home-page: https://pip.pypa.io/
Author: The pip developers
Author-email: <email address hidden>
License: MIT
Location: /usr/lib/python2.7/dist-packages
Requires:
Classifiers:
  Development Status :: 5 - Production/Stable
  Intended Audience :: Developers
  License :: OSI Approved :: MIT License
  Topic :: Software Development :: Build Tools
  Programming Language :: Python :: 2
  Programming Language :: Python :: 2.6
  Programming Language :: Python :: 2.7
  Programming Language :: Python :: 3
  Programming Language :: Python :: 3.3
  Programming Language :: Python :: 3.4
  Programming Language :: Python :: 3.5
  Programming Language :: Python :: Implementation :: PyPy
Entry-points:
  [console_scripts]
  pip = pip:main
  pip2 = pip:main
  pip2.7 = pip:main
---
Metadata-Version: 2.1
Name: tox
Version: 3.1.1
Summary: virtualenv-based automation of test activities
Home-page: https://tox.readthedocs.org/
Author: holger krekel
Author-email: <email address hidden>
Installer: pip
License: http://opensource.org/licenses/MIT
Location: /home/osboxes/.local/lib/python2.7/site-packages
Requires: packaging, py, six, pluggy, virtualenv
Classifiers:
  Development Status :: 5 - Production/Stable
  Framework :: tox
  Intended Audience :: Developers
  License :: OSI Approved :: MIT License
  Operating System :: POSIX
  Operating System :: Microsoft :: Windows
  Operating System :: MacOS :: MacOS X
  Topic :: Software Development :: Testing
  Topic :: Software Development :: Libraries
  Topic :: Utilities
  Programming Language :: Python :: 2
  Programming Language :: Python :: 2.7
  Programming Language :: Python :: 3
  Programming Language :: Python :: 3.4
  Programming Language :: Python :: 3.5
  Programming Language :: Python :: 3.6
Entry-points:
  [console_scripts]
  tox = tox:cmdline
  tox-quickstart = tox._quickstart:main
You are using pip version 8.1.1, however version 19.0.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.