title: ImportError: No module named requests - even though it is installed
body: <p>I'm running <code>Mac OS X</code> and <code>Python</code> (version 2.7).
  Apparently I'm missing <code>requests</code>, but it should be installed.</p>
  
  <pre><code>$ python setup.py 
  Traceback (most recent call last):
    File "setup.py", line 1, in &lt;module&gt;
      import requests
  ImportError: No module named requests
  
  $ pip install requests
  Requirement already satisfied: requests in /usr/local/lib/python2.7/site-packages
  Requirement already satisfied: certifi&gt;=2017.4.17 in /usr/local/lib/python2.7/site-packages (from requests)
  Requirement already satisfied: chardet&lt;3.1.0,&gt;=3.0.2 in /usr/local/lib/python2.7/site-packages (from requests)
  Requirement already satisfied: idna&lt;2.7,&gt;=2.5 in /usr/local/lib/python2.7/site-packages (from requests)
  Requirement already satisfied: urllib3&lt;1.23,&gt;=1.21.1 in /usr/local/lib/python2.7/site-packages (from requests)
  </code></pre>