title: Change string format delimeters in python
body: <p>I'd like to template out some config files, but they are not compatible with python's
  <code>"this is a {template}".format(template='string')</code> formatting</p>
  
  <p>eg.  curly braces are part of the config (nginx config).</p>
  
  <p>Can you change the delimiters to something else?</p>
  
  <p>eg, <code>'this is a [template]'.format(template='string')</code></p>