无法使用selenium/python作为select列表项的目标

Question

class SignUpPage(AbstractPage):
    def __init__(self, driver):
        super(SignUpPage, self).__init__(driver)

    def open_sign_up_page(self):
        self.driver.find_element_by_css_selector('a.home-button.js-popup-link').click()
        return SignUpPage(self.driver)

    def sign_up(self, first_name, last_name, email, req_password, school_name, city_name):
        self.driver.find_element_by_id('moderator_first_name').send_keys(first_name)
        self.driver.find_element_by_id('moderator_last_name').send_keys(last_name)
        self.driver.find_element_by_id('moderator_email').send_keys(email)
        self.driver.find_element_by_id('moderator_password').send_keys(req_password)
        self.driver.find_element_by_id('moderator_password_confirmation').send_keys(req_password)
        self.driver.find_element_by_id('moderator_school_attributes_name').send_keys(school_name)
        self.driver.find_element_by_id('moderator_school_attributes_city').send_keys(city_name)
        **Select(self.driver.find_element_by_xpath('//*[@id="moderator_school_attributes_state"]')).select_by_visible_text('Alabama')**
        self.driver.find_element_by_xpath('//*[@id="new_moderator"]/div[8]/input').click()
        return PostSignUpPage(self.driver)

这是我填表的“脚本”

http://screencast.com/t/ofjvjgwH7->；select的源代码。在

我试着用xpath、id、css locator、name属性定位select项，但都没用。我得到的错误如下

File“/Library/Python/2.7/site-packages/selenium/webdriver/remote/错误处理程序.py“，第181行，在check\u响应中 引发异常_类（消息、屏幕、stacktrace） ElementNotVisibleException:消息：元素当前不可见，因此可能无法与进行交互 堆栈跟踪：