title: Python regex expression, what does +X mean?
body: <p>I'm having trouble figuring out what exactly this regex pattern is searching for mostly due to the number at the end. From what I can tell, it is saying search for any character that is not a-z and repeat it for the whole string. What does the 3 do?</p>
  
  <pre><code>   [^a-z.+3]
  </code></pre>
  
  <p>Thanks!</p>