title: Sort a nested list in python by inner list number
body: <p>say I have a nested list such as this,</p>
  
  <pre><code>[
      ['a', [2, 3, 7]], 
      ['j', [63, 4, 0]], 
      ['c', [1, 155, 10]], 
      ['z', [0, 77, 7]], 
      ['f', [100, 42, 9]]
  ]
  </code></pre>
  
  <p>How do sort this by the chosen largest number in the innermost list? For instance, if we wanted to sort it by the first integer in each element's list from largest to smallest, the result would be</p>
  
  <pre><code>[
      ['f', [100, 42, 9]], 
      ['j', [63, 4, 0]], 
      ['a', [2, 3, 7]], 
      ['c', [1, 155, 10]], 
      ['z', [0, 77, 7]]
  ]
  </code></pre>