title: 'too many values to unpack', iterating over a dict. key=>string, value=>list
body: <p>I am getting the <code>too many values to unpack</code> error. Any idea how I can fix this?</p>
  <pre><code>first_names = ['foo', 'bar']
  last_names = ['gravy', 'snowman']
  
  fields = {
      'first_names': first_names,
      'last_name': last_names,
  }        
  
  for field, possible_values in fields:  # error happens on this line
  </code></pre>