title: Sort cProfile output by percall when profiling a Python script
body: <p>I'm using <code>python -m cProfile -s calls myscript.py</code></p>
  
  <p><code>python -m cProfile -s percall myscript.py</code> does not work.</p>
  
  <p>The Python documentation says "Look in the Stats documentation for valid sort values.": <a href="http://docs.python.org/library/profile.html#module-cProfile" rel="noreferrer">http://docs.python.org/library/profile.html#module-cProfile</a>, which I cannot find.</p>