title: Insert line at middle of file with Python?
body: <p>Is there a way to do this? Say I have a file that's a list of names that goes like this:</p>
  
  <ol>
  <li>Alfred</li>
  <li>Bill</li>
  <li>Donald</li>
  </ol>
  
  <p>How could I insert the third name, "Charlie", at line x (in this case 3), and automatically send all others down one line? I've seen other questions like this, but they didn't get helpful answers. Can it be done, preferably with either a method or a loop?</p>