title: Python 3 file input change in binary mode
body: <p>In Python 3, when I opened a text file with mode string 'rb', and then did f.read(), I was taken aback to find the file contents enclosed in single quotes after the character 'b'.</p>
  
  <p>In Python 2 I just get the file contents.</p>
  
  <p>I'm sure this is well known, but I can't find anything about it in the doco.  Could someone point me to it?</p>