title: How does pylint remember scores from previous runs?
body: <p>In a typical pylint run, we get the following output:</p>
  
  <pre><code>Global evaluation
  -----------------
  Your code has been rated at 9.50/10 (previous run: 8.50/10)
  
  Duplication
  -----------
  
  +-------------------------+------+---------+-----------+
  |                         |now   |previous |difference |
  +=========================+======+=========+===========+
  |nb duplicated lines      |0     |0        |=          |
  +-------------------------+------+---------+-----------+
  |percent duplicated lines |0.000 |0.000    |=          |
  +-------------------------+------+---------+-----------+
  </code></pre>
  
  <p>I wonder how pylint remembers scores from previous runs - In the example above, the score from previous run was 8.5. </p>
  
  <p>I want to implement such a functionality in my own module, and I thought I should first find out how pylint implements the functionality.</p>
  
  <p>I searched for hidden folders where this data could be stored, but found none.</p>