title: removing sublists which contain empty sublists only at specific positions
body: <p>Consider the list:</p>
  <pre><code>list_1 = [
      [
          [1, 2, 3], [], [3, 4, 5], [], [4, 5, 6], [7, 8, 9], [9, 1, 0]
      ],
      [
          [0, 1, 2], [9, 0, 1], [], [0, 1, 3], [1, 1, 1], [9, 5, 6], [3, 6, 7]
      ],
      [
          [1, 2, 4], [4, 5, 6], [], [1, 0, 1], [0, 1, 1], [3, 9, 7], []
      ],
      [
          [1, 3, 4], [], [3, 5, 6], [], [], [], [0, 7, 0]
      ]
  ]
  
  </code></pre>
  <p>I want to remove a row if it contains empty list either at 1st , 3rd or 7th position.</p>
  <p>For example above the 2nd and 3rd rows must be removed.
  I tried this:</p>
  <pre><code>list_2 = [sublist for sublist in list_1 if all(x for x in sublist)]
  </code></pre>
  <p>How I call the index 1, 3, 7 in this?</p>