title: str.format() option is not working
body: <p>This code was taken from the tutorial:</p>
  
  <pre><code>def main():
      stri = "Hello, {person}"
      stri.format(person="James")
      print(stri) #prints "Hello, {person}"
  </code></pre>
  
  <p>Why the <code>format()</code> is not working?</p>