title: Uppercasing letters after '.', '!' and '?' signs in Python
body: <p>I have been searching Stack Overflow but cannot find the proper code for correcting e.g.</p>
  
  <pre><code>"hello! are you tired? no, not at all!"
  </code></pre>
  
  <p>Into:</p>
  
  <pre><code>"Hello! Are you tired? No, not at all!"
  </code></pre>