我正在尝试使用Selenium编写身份验证机器人程序，但遇到一个错误，无法完成代码！错误为**“AttributeError：“str”对象没有属性“start”"，您可以在下面的终端**中看到代码和错误。

代码：'

class LoginBot():

def __init__(self):
    #Excel reading
    wb = load_workbook('seo-fast_profiles.xlsx')
    sheet_ranges = wb['Work']
    self.login = sheet_ranges['A2'].value
    self.email = sheet_ranges['B2'].value
    self.passw = sheet_ranges['C2'].value

    #Optins and UserAgent
    user = UserAgent()

    options = webdriver.ChromeOptions()

    options.add_argument(user.random)

    self.browser = webdriver.Chrome(service=ChromeDriverManager().install(), options=options)

def close_browser(self):
    self.browser.close()
    self.browser.quit()

def login(self):
    browser = self.browser
    browser.get("https://seo-fast.ru/login")
    time.sleep(random.randrange(1, 3))

    username_input = browser.find_element(By.ID, "logusername")
    username_input.clear()
    username_input.send_keys(self.email)

    time.sleep(1)

    username_input.send_keys(Keys.ENTER)

    time.sleep(2)

    password_input = browser.find_element(By.ID, "logpassword")
    password_input.send_keys(self.passw)

    time.sleep(5)
    password_input.send_keys(Keys.ENTER)
    time.sleep(7)

    #cookies
    pickle.dump(browser.get_cookies(), open(f"{self.login}_cookies", "wb"))

    self.close_browser()

def xpath_exists(self, url):
    browser = self.browser
    try:
        browser.find_element(By.XPATH, url)
        exist = True
    except NoSuchElementException:
        exist = False
    return exist

bot = LoginBot()
bot.login()

'

错误：File "E:\Python\lib\site-packages\selenium\webdriver\chromium\webdriver.py", line 89, in __init__ self.service.start() AttributeError: 'str' object has no attribute 'start'

有人能解决吗？