Custom Admin Script unknown error

[SparklingDesire (Sparkling)]

I’m totally baffled by this situation:

I’ve been creating a simple admin past hour and I can’t seem to bypass this weird problem I’m getting

function for getting the player’s full name

local function findplayer(plr, part)
	if part ~= nil then
		if string.lower(part) == "me" then
			return plr.Name
		else
			local v = nil
			for _, v in pairs(game.Players:GetChildren()) do
				for i, j in ipairs(v.Name:split("")) do
					if string.lower(part) == string.lower(v.Name:sub(1, i)) then
						return v
					end
				end
			end
		end
	else
		return nil
	end
end

script for the walkspeed command

	local playername, speedval = string.match(msg, "^:walkspeed%s+(%S+)%s*(%d+)$")
	local shouldberealname = findplayer(plr, playername)
	-- name should always exist
	if shouldberealname ~= nil and tonumber(speedval) >= 0 then
		print(shouldberealname)
		print(speedval)
		game.Workspace:FindFirstChild(shouldberealname):WaitForChild("Humanoid").WalkSpeed = tonumber(speedval)
	else
		displayerror("Wrong Approach")
	end

when I perform
:walkspeed me 100, it works totally fine.
However,
:walkspeed sp 100 continued to error with the following:

ServerScriptService.sparkleadmin.command:40: attempt to index nil with 'WaitForChild'

So I thought it had something to do with my findplayer function not working so as you can see, in my main script I added

print("shouldberealname")

The first 2 line of the console is me doing :walkspeed me 100
Rest of the lines(including the error) are me doing :walkspeed spa 100

It surely fetches my player’s name well and I do not see the problem at al.

[SparklingDesire (Sparkling)]

solved it

if string.lower(part) == string.lower(v.Name:sub(1, i)) then
	return v
end

Clearly I returned v, which was an Instance of the player.
I should’ve returned v.Name