title: sorting list of lists and getting indices in unsorted list
body: <p>These are the logical steps that I need to perform on my list of lists</p>
  
  <pre><code>a = [[5,2],[7,4],[0,3]]
  </code></pre>
  
  <ol>
  <li><p>sort the list of lists in such a way that the output looks something like</p>
  
  <pre><code>7,5,4,3,2,0
  </code></pre></li>
  <li><p>take the coordinates of the sorted elements in the original list, which in this case should produce as output</p>
  
  <pre><code>(1,0)
  (0,0)
  (1,1)
  (2,1)
  (0,1)
  (2,0)
  </code></pre></li>
  </ol>
  
  <p>I tried using of <code>sort, sorted</code> and <code>argwhere</code> in different ways but I am not getting sensible results, I guess first of all because <code>sort</code> and <code>sorted</code> can sort a list following only one axis at a time</p>