new_contents: from seleniumbase import BaseCase
  
  
  class DownloadTests(BaseCase):
  
      def test_download_files(self):
          self.open("https://pypi.org/project/seleniumbase/#files")
          pkg_header = self.get_text("h1.package-header__name")
          pkg_name = pkg_header.replace(" ", "-")
          whl_file = pkg_name + "-py2.py3-none-any.whl"
          self.click('div#files a[href$="%s"]' % whl_file)
          self.assert_downloaded_file(whl_file)
          tar_gz_file = pkg_name + ".tar.gz"
          self.click('div#files a[href$="%s"]' % tar_gz_file)
          self.assert_downloaded_file(tar_gz_file)
  
subject: Add test for asserting downloaded files