input: Write a function to create a Selenium script in Python that automates the login process on a given website. The function should initialize a web driver, navigate to the specified website, locate and fill in the username and password fields, click the submit button, and then print a success message after a brief wait. If the provided input website is invalid or if the login fields cannot be located, the function should handle these cases appropriately.
  assert auto_login('http://www.example.com')=='Login successful!'
  assert auto_login('http://www.anotherwebsite.com')=='Login unsuccessful!'
  assert auto_login('http://www.nonexistentwebsite.com')=='Website not found!'
output: def auto_login(website):
      try:
          from selenium import webdriver
          from selenium.webdriver.common.by import By
          from selenium.webdriver.common.keys import Keys
          import time
          
          driver = webdriver.Chrome()
          driver.get(website)
          
          try:
              username = driver.find_element(By.ID, 'username')
              password = driver.find_element(By.ID, 'password')
              submit_button = driver.find_element(By.ID, 'submit')
              
              username.send_keys('your_username')
              password.send_keys('your_password')
              submit_button.click()
              
              time.sleep(2)
              return 'Login successful!'
          except:
              return 'Login unsuccessful!'
      except:
          return 'Website not found!'