Python- generate a symmetric list of list with half of nxn list of list data : <p>I have this list of list, and I would like to convert it into a symmetric list of list. What should I do? </p>

<pre><code> [[0, 8, 4, 10, 12, 9, 15, 8, 11, 5, 9, 4, 10],
     [0, 0, 7, 6, 8, 6, 7, 10, 12, 9, 8, 7, 5],
     [0, 0, 0, 7, 9, 5, 8, 5, 4, 8, 6, 10, 8],
     [0, 0, 0, 0, 6, 11, 5, 9, 8, 12, 11, 6, 9],
     [0, 0, 0, 0, 0, 7, 9, 6, 9, 8, 4, 11, 10],
     [0, 0, 0, 0, 0, 0, 10, 4, 3, 10, 6, 5, 7],
     [0, 0, 0, 0, 0, 0, 0, 10, 9, 8, 5, 9, 10],
     [0, 0, 0, 0, 0, 0, 0, 0, 11, 5, 9, 6, 7],
     [0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 11, 11, 6],
     [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 7, 5],
     [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 7],
     [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9],
     [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]]
</code></pre>
