title: Format string by adding a space before each uppercase letter
body: <p>I have a string: <code>HotelCityClass</code>. I want to add a space in-between each Uppercase letter (apart from the first). i.e. <code>Hotel City Class</code>.</p>
  
  <p>I have tried using re</p>
  
  <blockquote>
    <p>re.sub(r'[A-Z]', '', str_name)</p>
  </blockquote>
  
  <p>But this only replaces each uppercase. Is <code>re</code> the correct, fast approach?</p>