# File lib/cookiejar/jar.rb, line 190
    def expire_cookies session = false
      @domains.delete_if do |domain, paths|
        paths.delete_if do |path, cookies|
          cookies.delete_if do |cookie_name, cookie|
            cookie.expired? || (session && cookie.session?)
          end
          cookies.empty?
        end
        paths.empty?
      end
    end