from selenium.webdriver.support import expected_conditions as EC 解析

from selenium.webdriver.support import expected_conditions as EC 解析

expected_conditions是Selenium的一个模selenium.webdriver.support.expected_conditions，可以对网页上元素是否存在，可点击等等进行判断，一般用于断言或与WebDriverWait配合使用。

例如：

from selenium.webdriver.common.by import By
from selenium.webdriver.support.wait import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC


wait = WebDriverWait(self.driver,20)
wait.until(EC.presence_of_element_located((By.XPATH,'//div[@id="root"]')))#等到啥时候为止