How to create a shortcode using WP-PostViews plugin?

I am using the famous WP-PostViews plugin, which already comes with a function to call the most-viewed posts.

<?php if (function_exists('get_most_viewed')): ?>
   <ul>
      <?php get_most_viewed(); ?>
   </ul>
<?php endif; ?>

My question is: how to use the function get_most_viewed and create a shortcode for it in function.php?

I am no programmer and this task is beyond my current range to tackle.