title: Removing an element in a list if it is the same as the previous element
body: <p>I've been stuck on this for a while now. It sounds simple enough but here's the code I've been working with so far. Basically the function is passed a bunch of numbers in a list for example <code>a_list = [1,2,3,3,4,3]</code> and I should get <code>[1,2,3,4,3]</code></p>
  <pre><code>def remove_doubles(a_list):
      print()
      new_list = []
      for i in range(len(a_list)):
          if a_list[i] != a_list[i+1]:  
              new_list.append(a_list[i])
          return new_list
  </code></pre>