title: Gurobi Python: how to write nested sum in a constraint
body: <p>I have an optimization problem and I'm using Python and Gurobi to optimize it. In my problem formulation there is a constraint that has a nested sum.</p>
  
  <p><a href="https://i.stack.imgur.com/iqDFX.png" rel="noreferrer">constraint</a></p>
  
  <p>I've recently started learning python and I searched in gurobi documentation and example codes and I couldn't find any example of nested sum. </p>
  
  <p>I was wondering if anyone could help me solve this problem. Thanks in advance!</p>