title: How to fill an empty string which has already been created in python
body: <p>I have created an empty string:</p>
  
  <pre><code>s = ""
  </code></pre>
  
  <p>how can I append text to it?
      I know how to append something to a list like:</p>
  
  <pre><code>list.append(something)
  </code></pre>
  
  <p>but how one can append something to an empty string?</p>