Error on `python install.py` from line 4: `import pip`

[trwnh]

PS D:\Programs\Yugioh-bot> python install.py

Traceback (most recent call last):
  File "install.py", line 4, in <module>
    import pip
  File "...\pip\__init__.py", line 45, in <module>
    from pip.vcs import git, mercurial, subversion, bazaar  # noqa
  File "...\pip\vcs\mercurial.py", line 9, in <module>
    from pip.download import path_to_url
  File "...\pip\download.py", line 40, in <module>
    from pip._vendor import requests, six
  File "...\pip\_vendor\requests\__init__.py", line 98, in <module>
    from . import packages
  File "...\pip\_vendor\requests\packages.py", line 12, in <module>
    sys.modules['pip._vendor.requests.packages.' + mod] = sys.modules["pip._vendor." + mod]
KeyError: 'pip._vendor.urllib3.contrib'

Removing line 4: import pip fixes this and allows the installer to proceed, but then it crashes again at check_required_packages() NameError: name 'pip' is not defined for obvious reasons.

[trwnh]

Solved -- somehow updated back to pip 9.0.2, reran install_requirements.txt and pip 9.0.1 worked. Perhaps a good idea to explicitly state this in the documentation.