title: How to keep only single copy of sublists with same elements (but in different order) from a bigger list?
body: <p>I have  a list </p>
  
  <p><code>[[1, -2, 3], [1, -2, -4], [1, -2, 1], [3, -2, 1], [-4, 1, 2]]</code></p>
  
  <p>and I want to keep single copy  of the sub lists with exact same elements. i.e remove  </p>
  
  <p><code>[[3, -2, 1], [-4, 1, 2]]</code></p>
  
  <p>and get following list.</p>
  
  <p><code>[[1, -2, 3], [1, -2, -4], [1, -2, 1]]</code></p>
  
  <p>What could be the fastest way of doing this?</p>
  
  <p>I am newbie, so language may be bad.</p>