title: Convert exception error to string
body: <p>I want to work with the error message from an exception but can't seem to convert it to a string.  I've read the os library man page but something is not clicking for me.</p>
  
  <p>Printing the error works:</p>
  
  <pre><code>try:
      os.open("test.txt", os.O_RDONLY)
  except OSError as err:
      print ("I got this error: ", err)
  </code></pre>
  
  <p>But this does not:</p>
  
  <pre><code>try:
      os.open("test.txt", os.O_RDONLY)
  except OSError as err:
      print ("I got this error: " + err)
  
  TypeError: Can't convert 'FileNotFoundError' object to str implicitly
  </code></pre>