title: Sum up only the second elements in a list of tuples
body: <p>Assuming I have this list of tuples: <code>[('3', '20'), ('1', '50'), ('2', '50')]</code>, how would I go about summing up only the second element in each tuple? So in this example, the sum would be 120. Also, would I have to convert the numbers to integers beforehand for the <code>sum()</code> function to work?</p>