title: How to remove combinations in one list that are present in another list?
body: <p>I have two lists that contain tuples.</p>
  <p>I want to remove all the combinations in list <code>seq2</code> that are elements of list <code>k1</code>. How can I do this?</p>
  <pre><code>from itertools import permutations
  
  seq2 = permutations(['p', 'y', 't', 'h', 'o', 'n'], 5)
  
  k2 = []
  k1 = [('y','h'),('p','o'),('h','n'),('t','p'),('n','o')]
  
  for j in list(seq2):
     k2.append(j)
  </code></pre>