input: Write a function to automate the login process on a given website using Selenium. If the login is successful, print "Login successful!". If the website is not provided, return nothing.
  from selenium import webdriver
  from selenium.webdriver.common.keys import Keys
  import time
  
  def automate_login(website=''):
      if not website:
          return
      driver = webdriver.Chrome()
      driver.get(website)
      username = driver.find_element_by_name('username')
      username.send_keys('username')
      password = driver.find_element_by_name('password')
      password.send_keys('password')
      submit_button = driver.find_element_by_name('submit')
      submit_button.click()
      time.sleep(5)
      print('Login successful!')
      driver.close()
  
  assert automate_login('http://www.example.com') is None
  assert automate_login('http://www.anotherwebsite.com') is None
  assert automate_login('') is None
output: def automate_login(website=''):
      if not website:
          return
      driver = webdriver.Chrome()
      driver.get(website)
      username = driver.find_element_by_name('username')
      username.send_keys('username')
      password = driver.find_element_by_name('password')
      password.send_keys('password')
      submit_button = driver.find_element_by_name('submit')
      submit_button.click()
      time.sleep(5)
      print('Login successful!')
      driver.close()