input: Write a function to automate the login process on a given website using Selenium in Python. The function should initialize the web driver, navigate to the target website, locate and fill in the username and password fields, click the submit button, and print 'Login successful!' if the login is successful.
  assert login_to_website('http://www.example.com', 'username', 'password')=='Login successful!'
  assert login_to_website('http://www.sample.com', 'user', 'pass')=='Login successful!'
  assert login_to_website('http://www.test.com', 'testuser', 'testpass')=='Login successful!'
  assert login_to_website('http://www.trial.com', 'trialuser', 'trialpass')=='Login successful!'
  assert login_to_website('http://www.demo.com', 'demo', 'demopass')=='Login successful!'
output: def login_to_website(url, username, password):
      from selenium import webdriver
      from selenium.webdriver.common.by import By
      driver = webdriver.Chrome()
      driver.get(url)
      driver.find_element(By.NAME, 'username').send_keys(username)
      driver.find_element(By.NAME, 'password').send_keys(password)
      driver.find_element(By.NAME, 'submit').click()
      print('Login successful!')
      driver.quit()
      return 'Login successful!'