title: Refering to a directory in a Flask app doesn't work unless the path is absolute
body: <p>I downloaded nltk data into the data directory in my Flask app. The views reside in a blueprint in another directory on the same level as the data directory.  In the view I'm trying to set the path to the data, but it doesn't work.</p>
  
  <pre><code>nltk.data.path.append('../nltk_data/')
  </code></pre>
  
  <p>This doesn't work. If I use the whole path, it does work.</p>
  
  <pre><code>nltk.data.path.append('/home/username/myapp/app/nltk_data/')
  </code></pre>
  
  <p>Why does the first form not work?  How can I refer to the location of the data correctly?</p>