Updating a card's description with Trello API?

Recently, I have tried to make use of this Trello API module script, however, I noticed that it didn't have something that I wanted, so I tried to add on to it. I want to have a function to update a card's description as well. Here's how I implemented it:

function T:UpdateCard(cardID, description)
	local url
	if Private then
		getAddon()
		url = "https://api.trello.com/1/cards/"..tostring(cardID).."/desc"..addon
	else
		url = "https://api.trello.com/1/cards/"..tostring(cardID).."/desc"..addon
	end
	local dat = {
		value = description
	}
	local data = HS:JSONEncode(dat)
	local re = HS:PostAsync(url, data)
	local red = HS:JSONDecode(re)
	return red
end

I keep getting an Error: HTTP 404 (HTTP/1.0 404 Not Found) error even though it works perfectly find with other functions such as creating a card.

If you are willing to help me with this question, please take a few minutes to look at the source code of the module script I linked earlier.

Also, here is the actual API.