title: Django Rest Framework ListField and DictField
body: <p>I am having struggle with understanding <code>ListField</code> and <code>DictField</code>. I want to use it as a field on a serializer. I have a <code>ListField</code> which probably will contain many <code>DictField</code>. I tried to write a serializer as below:</p>
  
  <pre><code>class StopOncomingSerialier(serializers.Serializer):
      idn = serializers.IntegerField(read_only=True)
      buses = serializers.ListField(
          child=serializers.DictField(
              idn=serializers.IntegerField(read_only=True),
              stops_left=serializers.IntegerField(read_only=True)
          ),
      read_only=True
      )
  </code></pre>
  
  <p>I know, it does not make sense, since the documentation says <code>DictField</code> and <code>ListField</code> take <code>child</code> as argument. And so, the code above naturally raised error:</p>
  
  <blockquote>
    <p><strong>TypeError:</strong> __init__() got an unexpected keyword argument 'stops_left'</p>
  </blockquote>
  
  <h3>Desired Output</h3>
  
  <pre><code>{
      "idn": 1,
      "buses": [
          {"idn": 11, "stops_left": 4},
          {"idn": 12, "stops_left": 15}
      ]
  }
  </code></pre>
  
  <p>How to achieve this? <code>buses</code> is a list and might contain as many elements as I want. </p>
  
  <hr>
  
  <h1>Environment</h1>
  
  <ul>
  <li>python 3.5.1</li>
  <li>django 1.9.6</li>
  <li>django-rest-framework 3.3.3</li>
  </ul>