title: When I do pip --version it show the error as ImportError: No module named pyparsing
body: <p>I tried installing/uninstalling <strong>pyparsing</strong> as well and it does not work. I am stuck with this and I have to install additional libraries as well.</p>
  
  <p>Here is the error message:</p>
  
  <pre><code>Traceback (most recent call last): 
  File "/usr/bin/pip", line 5, in &lt;module&gt;
      from pkg_resources import load_entry_point
  File "/home/rachana/.local/lib/python2.7/site-packages/pkg_resour‌​ces/__init__.py", line 72, in &lt;module&gt;
      import packaging.requirements
  File "/home/rachana/.local/lib/python2.7/site-packages/packaging/‌​requirements.py", line 9, in &lt;module&gt;
      from pyparsing import stringStart, stringEnd, originalTextFor, ParseException
  ImportError: No module named pyparsing
  </code></pre>
  
  <p>How can I fix this?</p>