title: Installation of pipenv on Windows fails
body: <p>I am working on a website with Django Heroku template. I want to work on this website on my Windows computer, and one of the requirements to work with Heroku and Python is to have pipenv (the project has a Pipfile).</p>
  
  <p>To install pipenv on Windows, I have tried two commands in the cmd terminal, which gave approximately the same error:</p>
  
  <pre><code>pip install pipenv
  </code></pre>
  
  <p>results in</p>
  
  <pre><code>Collecting pipenv
    Using cached pipenv-11.9.0.tar.gz
      Complete output from command python setup.py egg_info:
      error in pipenv setup command: 'install_requires' must be a string or list of strings containing valid project/version requirement specifiers; Expected version spec in pathlib;python_version&lt;"3.4" at ;python_version&lt;"3.4"
  
      ----------------------------------------
  Command "python setup.py egg_info" failed with error code 1 in C:\Users\myUserName\AppData\Local\Temp\pip-build-267yrlop\pipenv\
  </code></pre>
  
  <p>And:</p>
  
  <pre><code>easy_install -U pipenv
  </code></pre>
  
  <p>results in</p>
  
  <pre><code>Searching for pipenv
  Reading https://pypi.python.org/simple/pipenv/
  Best match: pipenv 11.9.0
  Downloading https://pypi.python.org/packages/aa/43/e7426676c659fa3c1db28653ceee3571efbaaec2d2795bca00212989268a/pipenv-11.9.0.tar.gz#md5=0cdefd8434dc2b30415708d517730dcb
  Processing pipenv-11.9.0.tar.gz
  Writing C:\Users\myUserName\AppData\Local\Temp\easy_install-p2bvwljy\pipenv-11.9.0\setup.cfg
  Running pipenv-11.9.0\setup.py -q bdist_egg --dist-dir C:\Users\myUserName\AppData\Local\Temp\easy_install-p2bvwljy\pipenv-11.9.0\egg-dist-tmp-vfore9pv
  error: Setup script exited with error in pipenv setup command: 'install_requires' must be a string or list of strings containing valid project/version requirement specifiers; Expected version spec in pathlib;python_version&lt;"3.4" at ;python_version&lt;"3.4"
  </code></pre>
  
  <p>I don't really understand the error message. It seems like an error in the setup script of pipenv but most likely isn't. Or is it expecting a Python version lower than 3.4? (if so, how do I install it with my Python 3.5?)</p>
  
  <p>EDIT: I've tried with admin rights, in and out of a virtualenv, but same result.</p>