title: ImportError: No module named 'twisted'
body: <p>I'm new to python and I'm writing a simple TCP server <code>Server.py</code>, and I'm trying to import the reactor using this line of code
  <code>from twisted.internet import reactor</code>
  The problem is when I run the code I get this error</p>
  
  <pre><code>/Library/Frameworks/Python.framework/Versions/3.5/bin/python3.5     /Users/Nora/PycharmProjects/Server/Server.py
  Traceback (most recent call last):
    File "/Users/Nora/PycharmProjects/Server/Server.py", line 2, in &lt;module&gt;
      from twisted.internet import reactor
  ImportError: No module named 'twisted'
  </code></pre>
  
  <p>Note that I am using OS X Yosemite, and I have installed a new python version 3.5, how can I go back to the system built in version which already has twisted?</p>