      """
      Represents the instance, or a property on the instance, using hyperlinking.
      """
      pk_url_kwarg = 'pk'
      slug_field = 'slug'
      slug_url_kwarg = None  # Defaults to same as `slug_field` unless overridden
  
 
</s> remove     read_only = True
 </s> add  </s> remove         kwargs = {self.pk_url_kwarg: obj.pk}
 </s> add         lookup_field = getattr(obj, self.lookup_field)
        kwargs = {self.lookup_field: lookup_field}
    lookup_field = 'pk'
    read_only = True

    # These are all pending deprecation
      """
      Represents the instance, or a property on the instance, using hyperlinking.
      """
    lookup_field = 'pk'
    read_only = True

    # These are all pending deprecation
      pk_url_kwarg = 'pk'
      slug_field = 'slug'
      slug_url_kwarg = None  # Defaults to same as `slug_field` unless overridden
  
keep keep add keep keep keep keep
 HyperlinkedIdentityField uses `lookup_field` kwarg.

According to the [Serializers API Guide][1], `HyperlinkedIdentityField`
takes `lookup_field` as a kwarg like the other related fields and the
generic views. However, this was not actually implemented.

[1]: http://django-rest-framework.org/api-guide/serializers.html#hyperlinkedmodelserializer 
rest_framework/relations.py