title: count occurrence of a list in a list of lists
body: <p>Python </p>
  
  <p>I have a list of lists. like </p>
  
  <pre><code>A = [[x,y],[a,b],[c,f],[e,f],[a,b],[x,y]]
  </code></pre>
  
  <p>I want to count how many times each list occurred in the main list. </p>
  
  <p>My output should be like</p>
  
  <pre><code>[x,y] = 2
  [a,b] = 2
  [c,f] = 1 
  [e,f] = 1
  </code></pre>