title: Python list group and sum with more fields
body: <p>I have a list with two integer fields which I would like to sum  (string,integer, integer)</p>
  
  <pre><code>myList= [[["26-07-2017",2,0], ["26-07-2017",3,0], ["27-07-2017",1,0], ["27-07-2017",0,1]]]
  </code></pre>
  
  <p>Now I would like to group by date and sum the int fields. So the output should be like this: </p>
  
  <pre><code>sumList= [[["26-07-2017",5,0], ["27-07-2017",1,1]]]
  </code></pre>
  
  <p>How can I accomplish this? Thank you for the answer. </p>