title: pylint3 Variable name "fl" doesn't conform to snake_case naming style (invalid-name)
body: <p>According to this <a href="http://pylint-messages.wikidot.com/messages:c0103" rel="nofollow noreferrer">pylint-wiki</a>, it seems that 2 letter variable names are ok:</p>
  <blockquote>
  <p>Variable  variable-rgx    [a-z_][a-z0-9_]{2,30}$</p>
  </blockquote>
  <p>But for some reason I get the following error:</p>
  <pre><code>Variable name &quot;fl&quot; doesn't conform to snake_case naming style (invalid-name)
  </code></pre>