title: How to configure paths to import from for flake8 in syntastic
body: <p>I configured <code>flake8</code> as the python checker in <code>syntastic</code> plugin.  Problem is my project has some extra paths added to <code>sys.path</code> at runtime.  I need somewhere to configure those paths, otherwise the checker will keep complaining <code>[F0401] Unable to import 'module'</code>.  So where can I do this.</p>
  
  <p><strong>UPDATE</strong></p>
  
  <p>Turns out that it is pylint checker that complains the import error.  flake8 seems do not care about this.  Following is the output of flake8.  And the solution to fix this for pylint plz refer to this question:<a href="https://stackoverflow.com/questions/1899436/pylint-unable-to-import-error-how-to-set-pythonpath">PyLint &quot;Unable to import&quot; error - how to set PYTHONPATH?</a></p>
  
  <pre><code>$ flake8 TestListPage.py
  TestListPage.py:7:1: W191 indentation contains tabs
  TestListPage.py:8:1: W191 indentation contains tabs
  TestListPage.py:9:1: W191 indentation contains tabs
  TestListPage.py:10:1: W191 indentation contains tabs
  TestListPage.py:12:1: W191 indentation contains tabs
  TestListPage.py:13:1: W191 indentation contains tabs
  TestListPage.py:15:1: W191 indentation contains tabs
  TestListPage.py:16:1: W191 indentation contains tabs
  TestListPage.py:18:1: W191 indentation contains tabs
  </code></pre>
  
  <p>Also the answer of @lcd047 may help for other plugins using the python interpreter.  But it does not fix the pylint error.</p>
  
  <pre><code>$ echo $PYTHONPATH
  /cygdrive/c/---------------/
  $ pylint TestListPage.py
  ************* Module TestListPage
  W:  7,0: Found indentation with tabs instead of spaces
  ...
  C: 45,0: Line too long (95/80)
  ...
  C:  1,0: Missing docstring
  F:  3,0: Unable to import 'guis'
  </code></pre>