title: Accumulate items in a list of tuples
body: <p>I have a list of tuples that looks like this:</p>
  
  <pre><code>lst = [(0, 0), (2, 3), (4, 3), (5, 1)]
  </code></pre>
  
  <p>What is the best way to accumulate the sum of the first and secound tuple elements? Using the example above, I'm looking for the best way to produce this list:</p>
  
  <pre><code>new_lst = [(0, 0), (2, 3), (6, 6), (11, 7)]
  </code></pre>
  
  <p>I am looking for a solution in Python 2.6</p>