How to find the definition of an operator in the python source code?
<p>I became curious about the implementation of the "in" (<code>__contains__</code>?) operator in python due to <a href="http://stackoverflow.com/questions/9089400/python-set-in-operator-uses-equality-or-identity">this SO question</a>. I downloaded the source code and tried to grep, browse, etc. to find some base definition of it, but I haven't been successful. Could someone show me a way to find it?</p>

<p>Of course a general approach to finding that kind of thing would be best so anyone like me can learn to fish for next time.</p>

<p>I'm using 2.7 but if the process is totally different for 3.x, that would be nice to have both techniques.</p>
