# File lib/dm-core/resource.rb, line 516
    def update_attributes(hash, *update_only)
      unless hash.is_a?(Hash)
        raise ArgumentError, "Expecting the first parameter of " +
          "update_attributes to be a hash; got #{hash.inspect}"
      end
      loop_thru = update_only.empty? ? hash.keys : update_only
      loop_thru.each { |attr|  send("#{attr}=", hash[attr]) }
      save
    end