title: Django Rest Framework Serializer lost ListField data during validation
body: <p>I want to serialize a list of strings as well as some other fields. Somehow it doesn't appear to be in validate data.</p>
  
  <pre><code>class OptionsSerializer(serializers.Serializer):
      lst = serializers.ListField(
          serializers.CharField(),
      )
      field_a = serializers.CharField()
      field_b = serializers.IntegerField()
  </code></pre>
  
  <p><strong>Request payload:</strong></p>
  
  <pre><code>{"lst":["abc"],"field_a":"some text","field_b":1}
  </code></pre>
  
  <p><strong>Debugger output:</strong></p>
  
  <pre><code>ipdb&gt; serializer.is_valid()
  True
  ipdb&gt; serializer.validated_data
  OrderedDict([('field_a', 'some text'), ('field_b', 1)])
  </code></pre>
  
  <p>Any ideas about why is it so?</p>