title: Add empty elements to a list
body: <pre><code>phrase = "TEST PHRASE"
  progress = []
  
  for letter in phrase:
      if letter != None:
          progress.append("-")
      else:
          progress.append("")
  
  print progress
  </code></pre>
  
  <p>So I want this to give me ["-","-","-","-","","-","-","-","-","-"]
  So that I can string.join them and get ---- -----
  Basically a hidden string. 
  But ['-', '-', '-', '-', '-', '-', '-', '-', '-', '-', '-']
  is what I'm getting. No empty element to mark the space. </p>