Cucumber/Capybara: check that a page does NOT have content?

Using Cucumber and Capybara, is there a way to verify that a string is NOT present on a page?

For example, how would I write the opposite of this step:

Then /^I should see "(.*?)"$/ do |arg1|
  page.should have_content(arg1)
end

This passes if arg1 is present.

How would I write a step that fails if arg1 is found?