# File lib/dm-timestamps.rb, line 35
      def timestamps(*names)
        raise ArgumentError, 'You need to pass at least one argument' if names.empty?

        names.each do |name|
          case name
            when *TIMESTAMP_PROPERTIES.keys
              type = TIMESTAMP_PROPERTIES[name].first
              property name, type, :nullable => false, :auto_validation => false
            when :at
              timestamps(:created_at, :updated_at)
            when :on
              timestamps(:created_on, :updated_on)
            else
              raise InvalidTimestampName, "Invalid timestamp property name '#{name}'"
          end
        end
      end