How to scroll down in Android on appium using python

I have tried script below but showing error

element_to_tap = driver.find_element_by_xpath(xpath)
element_to_drag_to = driver.find_element_by_xpath(xpath)
driver.scroll(element_to_tap, element_to_drag_to)

Error: An element could not be located on the page using the given search parameters.

The script can’t locate the element which is out of the screen. e.g. need scroll down first.