Selenium Page down by ActionChains

I had to click on the body for the Keys.PAGE_DOWN to work but didn't need to use the action chain:

from selenium.webdriver.common.keys import Keys

body = driver.find_element_by_css_selector('body')
body.click() 

body.send_keys(Keys.PAGE_DOWN) 

from: https://stackoverflow.com/questions/39471163/selenium-page-down-by-actionchains/39472743