title: How to round every element in a list of lists?
body: <p>My intention is to get <code>[[1.23,2.45],[2.35,9.87])</code>.<br />
  The following gives one single element to be <code>1.23</code>, why is this so?</p>
  
  <pre><code>b =[[1.234,2.454],[2.352,9.873]]
  
  def get_round(x):
      for i in x:
          if type(i) ==list:
              for each_i in i: 
                  return round(each_i,2)
          else:
              return round(i,2)
  
  get_round(b)   
  </code></pre>
  
  <p>How can I round every single elements and without change the existing data structure?</p>