selenium驱动chrome-等待等待下载完成后再下载下一个

def every_downloads_chrome(driver,i):

        if not driver.current_url.startswith("chrome://downloads"):
            driver.get("chrome://downloads/")
        a=driver.execute_script('return document.querySelector("body > downloads-manager").shadowRoot.querySelector("#frb{}").shadowRoot.querySelector("#description").textContent.search("/")'.format(i))
        if a==-1:
            return False
            #这时候就睡眠
          
        else:
            return True