# File lib/chef/resource.rb, line 181
    def self.identity_attr(attr_name=nil)
      @identity_attr ||= nil
      @identity_attr = attr_name if attr_name

      # If this class doesn't have an identity attr, we'll defer to the superclass:
      if @identity_attr || !superclass.respond_to?(:identity_attr)
        @identity_attr
      else
        superclass.identity_attr
      end
    end