title: Why twisted is not installed on CentOS, Python version is 2.7 and pip is using same python command
body: <pre><code>sudo pip install twisted
  </code></pre>
  
  <blockquote>
    <p>Collecting twisted</p>
  </blockquote>
  
  <p>Using cached Twisted-15.5.0.tar.bz2</p>
  
  <pre><code>Complete output from command python setup.py egg_info:
  Traceback (most recent call last):
    File "&lt;string&gt;", line 20, in &lt;module&gt;
    File "/tmp/pip-build-WTSzv5/twisted/setup.py", line 64, in &lt;module&gt;
      main(sys.argv[1:])
    File "/tmp/pip-build-WTSzv5/twisted/setup.py", line 45, in main
      from twisted.python.dist import (
    File "./twisted/__init__.py", line 55, in &lt;module&gt;
      _checkRequirements()
    File "./twisted/__init__.py", line 17, in _checkRequirements
      raise ImportError("Twisted requires Python 2.7 or later.")
  ImportError: Twisted requires Python 2.7 or later.
  
  
  ----------------------------------------
  </code></pre>
  
  <p>Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-WTSzv5/twisted</p>
  
  <pre><code>pip --version
  </code></pre>
  
  <p>pip 7.1.2 from /usr/local/lib/python2.7/site-packages/pip-7.1.2-py2.7.egg (python 2.7)</p>