title: sklearn_extra installation issue
body: <p>[in]:</p>
  <pre class="lang-py prettyprint-override"><code>from sklearn_extra.cluster import KMedoids
  </code></pre>
  <p>[out]:</p>
  <pre><code>ModuleNotFoundError: No module named 'sklearn_extra'
  </code></pre>
  <p>Then, I tried installing sklearn_extra via</p>
  <p>[in]:</p>
  <pre class="lang-py prettyprint-override"><code>python -m pip install sklearn_extra
  </code></pre>
  <p>[out]:</p>
  <pre class="lang-py prettyprint-override"><code>ERROR: Could not find a version that satisfies the requirement sklearn_extra (from versions: none)
  ERROR: No matching distribution found for sklearn_extra
  </code></pre>
  <p>Then, I went to installation part of the website(<a href="https://scikit-learn-extra.readthedocs.io/en/latest/install.html" rel="nofollow noreferrer">https://scikit-learn-extra.readthedocs.io/en/latest/install.html</a>) and did what it said:</p>
  <pre><code>Installation
  Dependencies
  scikit-learn-extra requires,
  
  Python (&gt;=3.5)
  
  scikit-learn (&gt;=0.21), and its dependencies
  
  Cython (&gt;0.28)
  
  User installation
  Latest development version can be installed with,
  
  pip install https://github.com/scikit-learn-contrib/scikit-learn-extra/archive/master.zip
  </code></pre>
  <p>[in]:</p>
  <pre class="lang-py prettyprint-override"><code>pip install https://github.com/scikit-learn-contrib/scikit-learn-extra/archive/master.zip
  </code></pre>
  <p>[out]:</p>
  <pre><code>  ERROR: Command errored out with exit status 1:
     command: 'c:\users\m\appdata\local\programs\python\python37\python.exe' 'c:\users\m\appdata\local\programs\python\python37\lib\site-packages\pip' install --ignore-installed --no-user --prefix 'C:\Users\m\AppData\Local\Temp\pip-build-env-yopprv13\overlay' --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- setuptools wheel 'cython&gt;=0.28' numpy==1.14.5
         cwd: None
    Complete output (14 lines):
    Traceback (most recent call last):
      File &quot;c:\users\m\appdata\local\programs\python\python37\lib\runpy.py&quot;, line 193, in _run_module_as_main
        &quot;__main__&quot;, mod_spec)
      File &quot;c:\users\m\appdata\local\programs\python\python37\lib\runpy.py&quot;, line 85, in _run_code
        exec(code, run_globals)
      File &quot;c:\users\m\appdata\local\programs\python\python37\lib\site-packages\pip\__main__.py&quot;, line 16, in &lt;module&gt;
        from pip._internal.main import main as _main  # isort:skip # noqa
      File &quot;c:\users\m\appdata\local\programs\python\python37\lib\site-packages\pip\_internal\main.py&quot;, line 8, in &lt;module&gt;
        import locale
      File &quot;c:\users\m\appdata\local\programs\python\python37\lib\locale.py&quot;, line 16, in &lt;module&gt;
        import re
      File &quot;c:\users\m\appdata\local\programs\python\python37\lib\re.py&quot;, line 143, in &lt;module&gt;
        class RegexFlag(enum.IntFlag):
    AttributeError: module 'enum' has no attribute 'IntFlag'
  </code></pre>
  <p>I checked versions of Cython,Python and sklearn they satisfy the required range.</p>
  <p>Edit: the solution is to uninstall enum34 for me thanks to Balraj Ashwatt's comment.</p>
  <pre class="lang-py prettyprint-override"><code>pip uninstall -y enum34
  </code></pre>
  <p>Then I was able to install sklearn_extra</p>