title: how to define functions in ipython configuration file?
body: <p>Using ipython 0.11 if I type a function definition, like</p>
  
  <pre><code>def f(s): print s
  </code></pre>
  
  <p>then I can use that function in that ipython session, but I don't know how to define that 
  in the ipython_config.py file. 
  If I just type the function definition in the file and try to use the function it it undefined.</p>
  
  <p>Any idea?</p>