text: from time import sleep
  from selenium.webdriver import Firefox
  
  from selenium.webdriver.support.wait import WebDriverWait
  from selenium.webdriver.support.expected_conditions import alert_is_present
  
  
  url = 'https://selenium.dunossauro.live/aula_11_a.html'
  
  browser = Firefox()
  wdw = WebDriverWait(browser, 30)
  
  browser.get(url)
  
  sleep(2)
  
  browser.find_element_by_id('alertd').click()
  
  print('before wait alert...')
  alert = wdw.until(alert_is_present())
  print('after wait alert.')
  
  alert.accept()  # alerta
  