      # "HTTP 201 Created" responses.
      url_field_name = api_settings.URL_FIELD_NAME
  
      def create(self, validated_data):
          """
          We have a bit of extra checking around this in order to provide
          descriptive messages when something goes wrong, but this method is
 
</s> remove     # Default `create` and `update` behavior...
 </s> add     # The field name for hyperlinked identity fields. Defaults to 'url'.
    # You can modify this using the API setting.
    #
    # Note that if you instead need modify this on a per-serializer basis,
    # you'll also need to ensure you update the `create` method on any generic
    # views, to correctly handle the 'Location' response header for
    # "HTTP 201 Created" responses.
    url_field_name = api_settings.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             [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
    # Default `create` and `update` behavior...
      # "HTTP 201 Created" responses.
      url_field_name = api_settings.URL_FIELD_NAME
  
    # Default `create` and `update` behavior...
      def create(self, validated_data):
          """
          We have a bit of extra checking around this in order to provide
          descriptive messages when something goes wrong, but this method is
keep keep add keep keep keep keep
 Added url_field_name class attribute to ModelSerializer. Closes #3106. 
rest_framework/serializers.py