How can I install multiple versions of Python on latest OS X and use them in parallel?
<p>I want to run tests with multiple Python versions on OS X 10.11, including:</p>

<ul>
<li>Python 2.6 - ?!</li>
<li>Python 2.7 - default - solved</li>
<li>Python 3.4 - ?!</li>
<li>Python 3.5 - installed via brew - works well</li>
<li>Conda Python 3.5 - ?!</li>
</ul>

<p>I want to run the tests via <code>tox</code> so tox needs to be able to find them. Sadly it seems that brew doesn't want to install 3.4 since they added 3.5 and I obviously do not want to remove 3.5 one.</p>