title: in IntelliJ, showing "No module named xxx", but "xxx" is actually installed in my system
body: <p>My IntelliJ version is <strong>15.0.3</strong>, and have python plugin installed.</p>
  
  <p>And when I open a python file in IntelliJ it's like below
  <a href="https://i.stack.imgur.com/qrmPE.png" rel="noreferrer"><img src="https://i.stack.imgur.com/qrmPE.png" alt="enter image description here"></a></p>
  
  <p>Situation here is like below:</p>
  
  <ol>
  <li>when I import these flagged modules in terminal, everything works fine.</li>
  <li>running this python file in IntelliJ, is also fine</li>
  </ol>
  
  <p>It's <strong>only the red underlying warning</strong> annoying me.</p>
  
  <p>I tried <a href="https://stackoverflow.com/questions/6102908/how-do-i-get-intellij-to-recognize-common-python-modules">this one</a>, <a href="https://stackoverflow.com/questions/13994846/intellij-python-plugin-run-classpath">this one</a> and <a href="https://stackoverflow.com/questions/26069254/importerror-no-module-named-bottle-pycharm">this one</a>, but none works for me.</p>
  
  <p>Could anyone please tell me how to get rid of it? Thanks a lot.</p>