title: Readline numbers as integers, not strings
body: <p>I have a data list in a file that I am trying to mutate.
  I want to change some of the data within the file, but wherever there is a digit in the list, it returns it as a string. If I wanted to return another integer back to the list so when I re-read it back, it will be in int, can I just use <code>int(10)</code>, for example, <code>10</code> and not <code>"10"</code>? As it seems readlines turns everything into a str.</p>