  
      * A 'url' field is included instead of the 'id' field.
      * Relationships to other instances are hyperlinks, instead of primary keys.
      """
      serializer_related_class = HyperlinkedRelatedField
  
      def get_default_field_names(self, declared_fields, model_info):
          """
          Return the default list of field names that will be used if the
          `Meta.fields` option is not specified.
 
</s> remove             field_class = ChoiceField
 </s> add             field_class = self.serializer_choice_field </s> remove         field_class = HyperlinkedIdentityField
 </s> add         field_class = self.serializer_url_field </s> remove     serializer_related_class = PrimaryKeyRelatedField
 </s> add     serializer_related_field = PrimaryKeyRelatedField
    serializer_url_field = HyperlinkedIdentityField
    serializer_choice_field = ChoiceField </s> remove         field_class = self.serializer_related_class
 </s> add         field_class = self.serializer_related_field
    serializer_related_field = HyperlinkedRelatedField
  
      * A 'url' field is included instead of the 'id' field.
      * Relationships to other instances are hyperlinks, instead of primary keys.
      """
    serializer_related_field = HyperlinkedRelatedField
  
      def get_default_field_names(self, declared_fields, model_info):
          """
          Return the default list of field names that will be used if the
          `Meta.fields` option is not specified.
keep keep keep keep replace keep keep keep keep keep
 Minor cleanups/improvements to ModelSerializer API 
rest_framework/serializers.py