How do I emulate a keypress inside a Vim function?

I'll start with code function BigScrollUp() let count = 20 while count > 0 "Press" CTRL-Y <-- how do I emulate this? sleep 5m count -= 1 endwhile endfunction I want to create a function to quickly scroll up and down, with animation so that I can keep track of where I am going.

[kiyo_hiko]

function hogera ()\nnormal <write any key emulation here,>\nendfunction