  
          elif hasattr(model_class, field_name):
              return self.build_property_field(field_name, model_class)
  
          elif field_name == api_settings.URL_FIELD_NAME:
              return self.build_url_field(field_name, model_class)
  
          return self.build_unknown_field(field_name, model_class)
  
      def build_standard_field(self, field_name, model_field):
 
</s> remove             [api_settings.URL_FIELD_NAME] +
 </s> add             [self.url_field_name] + </s> remove             extra_kwargs[api_settings.URL_FIELD_NAME] = kwargs
 </s> add             extra_kwargs[self.url_field_name] = kwargs </s> remove             kwargs = extra_kwargs.get(api_settings.URL_FIELD_NAME, {})
 </s> add             kwargs = extra_kwargs.get(self.url_field_name, {}) </s> remove             extra_kwargs[api_settings.URL_FIELD_NAME] = kwargs
 </s> add             extra_kwargs[self.url_field_name] = kwargs </s> remove             kwargs = extra_kwargs.get(api_settings.URL_FIELD_NAME, {})
 </s> add             kwargs = extra_kwargs.get(self.url_field_name, {})
        elif field_name == self.url_field_name:
  
          elif hasattr(model_class, field_name):
              return self.build_property_field(field_name, model_class)
  
        elif field_name == self.url_field_name:
              return self.build_url_field(field_name, model_class)
  
          return self.build_unknown_field(field_name, model_class)
  
      def build_standard_field(self, field_name, model_field):
keep keep keep keep replace keep keep keep keep keep
 Added url_field_name class attribute to ModelSerializer. Closes #3106. 
rest_framework/serializers.py