title: How to define a function that calculate reciprocal rank and mean reciprocal rank in a list? (Python)
body: <p>I'm a beginner in python and I still not know so much about coding.<br/>
  This is what I got for Wikipedia : <br/></p>
  
  <p><img src="https://i.stack.imgur.com/tmmFF.jpg" alt="enter image description here"></p>