def format=(format)
      format = format.upcase

      unless(FORMATS.include?(format))
        raise ArgumentError, "Format must be one of #{FORMATS.join(',')}"
      end

      @format = format.upcase
    end
def format=(format)
      format = format.upcase

      unless(FORMATS.include?(format))
        raise ArgumentError, "Format must be one of #{FORMATS.join(',')}"
      end

      @format = format.upcase
    end
=== Options:
 * <tt>: