title: JSON [{"non_field_errors": ["Invalid data"]}]} Django Rest Framework
body: <p>I have some serializer where I have some elements and want it to POST it when I create POST method for InvoiceDictionarySerializer. Dont have any idea how to make it works properly. Any suggestions?</p>
  
  <p>My code looks as follow:</p>
  
  <pre><code>class InvoiceDictionaryElementSerializer(serializers.ModelSerializer):
  class Meta:
      model = InvoiceDictionaryElement
      fields = (
          'name', 'unit', 'quantity', 'value'
      )
  
  
  class InvoiceDictionarySerializer(serializers.ModelSerializer):
      invoice_elements = InvoiceDictionaryElementSerializer()
      class Meta:
          model = InvoiceDictionary
          fields = (
              'name', 'is_active', 'invoice_elements')
  </code></pre>
  
  <p>and my request for JSON:</p>
  
  <pre><code>{
  "name": "invoice", 
  "is_active": true, 
  "invoice_elements":  [{
          "name": "name", 
          "unit": "12", 
          "quantity": "15.00", 
          "value": "7.00"
      }]
  </code></pre>
  
  <p>}</p>
  
  <p>got error:</p>
  
  <pre><code>{"invoice_elements": [{"non_field_errors": ["Invalid data"]}]}
  </code></pre>
  
  <p>On my conslote output i have 400 error (bad request). Dont know that the syntax for JSON is bad or what?</p>