使用Selenium时未解释的空引用[重复]

from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException

driver = webdriver.Chrome()
try:
    element = driver.find_element_by_id("non_existent_id")
except NoSuchElementException:
    print("Element not found")

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

driver = webdriver.Chrome()
driver.get("http://example.com")
try:
    element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.ID, "element_id"))
    )
except TimeoutException:
    print("Element not found within the timeout period")

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

driver = webdriver.Chrome()
driver.get("http://example.com")
try:
    element = WebDriverWait(driver, 10).until(
        EC.visibility_of_element_located((By.XPATH, "//div[@class='dynamic-content']"))
    )
except TimeoutException:
    print("Dynamic content not visible within the timeout period")