title: How do you find common sublists between two lists?
body: <p>How do you find or keep only the sublists of a list if it the sublist is also present within another list?</p>
  
  <pre><code>lsta = [['a','b','c'],['c','d','e'],['e','f','g']]
  lstb = [['a','b','c'],['d','d','e'],['e','f','g']]
  </code></pre>
  
  <p>I'd like to do something like set(lsta) &amp; set(lstb) </p>
  
  <pre><code>Desired_List = [['a','b','c'],['e','f','g']]
  </code></pre>
  
  <p>The reason I'd like to do something like set is for it's speed as I'm doing this on a very large list where efficiency is quite important. </p>
  
  <p>Also, slightly unrelated, what if I wanted to subtract lstb from lsta to get</p>
  
  <pre><code>Desired_List2 = [['d','d','e']]
  </code></pre>