# File lib/dm-core/model/property.rb, line 116
      def properties(repository_name = default_repository_name)
        # TODO: create PropertySet#copy that will copy the properties, but assign the
        # new Relationship objects to a supplied repository and model.  dup does not really
        # do what is needed
        repository_name = repository_name.to_sym

        default_repository_name = self.default_repository_name

        @properties[repository_name] ||= if repository_name == default_repository_name
          PropertySet.new
        else
          properties(default_repository_name).dup
        end
      end