What's wrong in my script which giving decal on torso?

Hello! I made script which giving decal on torso when you gonna click brick, but it's not working any ideas what's wrong?

This is this script

local brick = script.Parent
local decal = brick:findFirstChild("Decal")

script.Parent.ClickDetector.MouseClick:connect(function(player)
    local humanoid = player.Parent:findFirstChild("Humanoid")
    local torso = player.Parent:findFirstChild("Torso")
    if torso ~= nil and humanoid ~= nil then
        local shirt = player.Parent:findFirstChild("Shirt Graphic")
        if shirt ~= nil then
            shirt.Graphic = decal.Texture
        else
            local altshirt = torso:findFirstChild("roblox")
            if altshirt ~= nil then
                altshirt.Texture = decal.Texture
            else
                print("Torso found. Shirt not found. Assumed to be a robot.")
            end
        end
    else
        print("Not a valid person! T-Shirt cannot be changed!")
    end
end)