Python+Selenium 在百度首页的输入框，点击照相机按钮，再点击上传文件按钮，报错：Message: invalid argument

from selenium import webdriver
from time import sleep

driver = webdriver.Chrome()
driver.maximize_window()
driver.implicitly_wait(10)

driver.get("http://www.baidu.com")
try:
    # 点击百度上面的照相机按钮
    driver.find_element_by_css_selector(".soutu-btn").click()
    # 点击选择文件按钮
    driver.find_element_by_css_selector(".upload-pic").click()

except Exception as e:
    driver.get_screenshot_as_file("error2.png")
    print(e)

sleep(3)
driver.quit()

在百度首页的输入框，点击照相机按钮上传文件
报错：

但是上传文件按钮用鼠标操作方法就可以执行，有没有哪位老哥知道为啥呀

        # 点击百度上面的照相机按钮
        driver.find_element(By.CSS_SELECTOR,".soutu-btn").click()
        # 点击选择文件按钮
        driver.find_element(By.CSS_SELECTOR,".upload-pic").click()