title: How do I fix there is no such module error in python 2.6?
body: <p>I've been using python 2.7 and after installation of python 2.7. All of the scripts have run successfully, but suddenly today, when I run python, it is recognized with python 2.6, so for one of the python packages I get the following error: </p>
  
  <pre class="lang-none prettyprint-override"><code>/Library/Frameworks/Python.framework/Versions/2.6/Resources/Python.app/Contents/MacOS/Python: 
  No module named htseq-count
  </code></pre>
  
  <p>i am not sure why it happens. The path environment variable for python is set to:</p>
  
  <pre class="lang-none prettyprint-override"><code>PATH="/Library/Frameworks/Python.framework/Versions/2.7/Resources/bin:${PATH}" export PATH
  </code></pre>
  
  <p>How do I fix this error?</p>