  
          if fields:
              return property_fields & set(as_tuple(fields))
  
          return property_fields - set(as_tuple(exclude_fields))
 
</s> remove             return property_fields & set(as_tuple(fields))
 </s> add             return property_fields & set(as_tuple(self.fields)) </s> remove         """Returns a set containing the names of validated properties on the model."""
        resource = self.view.resource
        model = getattr(resource, 'model', None)
        fields = getattr(resource, 'fields', self.fields)
        exclude_fields = getattr(resource, 'exclude_fields', self.exclude_fields)

        property_fields = set(attr for attr in dir(model) if
                              isinstance(getattr(model, attr, None), property)
 </s> add         """
        Returns a set containing the names of validated properties on the model.
        """
        property_fields = set(attr for attr in dir(self.model) if
                              isinstance(getattr(self.model, attr, None), property) </s> remove         return model_fields - set(as_tuple(exclude_fields))
 </s> add         return model_fields - set(as_tuple(self.exclude)) </s> remove 
    #print fields - (opts.fields + opts.many_to_many) 
    #for related in [rel.get_accessor_name() for rel in opts.get_all_related_objects()]:
    #    if fields and not related in fields:
    #        continue
    #    if exclude and related in exclude:
    #        continue
    #    data[related] = getattr(instance, related)
 </s> add         
        if extra_fields and f.name in extra_fields:
            extra_fields.remove(f.name) </s> remove             return form_cls(data, files)
 </s> add             return self.form(data, files)
        return property_fields - set(as_tuple(self.exclude))
  
          if fields:
              return property_fields & set(as_tuple(fields))
  
        return property_fields - set(as_tuple(self.exclude))
keep keep keep keep replace
 Sorting out resources.  Doing some crazy magic automatic url resolving stuff.  Yum. 
djangorestframework/resources.py