title: Can I format the docstring in python3
body: <p>I am trying to make a docstring that will accept replacement fields as follows</p>
  
  <pre><code>def run_tests(args):
      """run tests on methods in {0}
  
      usage: {0} --tests
      """.format(__file__)
      pass
  </code></pre>
  
  <p>but when I run <code>help(run_tests)</code> in the interpreter, I do not get the docstring.  If I remove {} and .format() the docstring returns as expected.</p>
  
  <p>I would like to see the output something like:</p>
  
  <pre><code>Help on function run_tests in module myfile:
  
  run_tests(args)
      runs tests on methods in myfile.py
  
      usage:  myfile.py --tests
  </code></pre>
  
  <p>Is there a way to do this in python3?</p>