[1.14] "function":"enchant_randomly" not working in loot tables

Hi, I am very new to modding so please excuse me if this is an obvious mistake.

I am making a block that when it is broken, drops a random enchanted book, but when I try it is not enchanted, here is my entry:

"type": "minecraft:item",
"name": "minecraft:enchanted_book",
"functions":[
    {
	"function":"enchant_randomly"
    }
]

Any help would be great, thanks!