How can i describe in Lua that no tool is selected?

I have a script and I only want it to work if the player has no tools selected. How could I define no tools being selected? Basically what I'm asking is, how can I say in Lua "when the player has no tool selected"? Someone suggested this function below, but It only works for an actual tool, not a Hopperbin script based tool like I have.

function isToolEquipped()
    local character = player.Character
    if character then
        for _, child in next, character:GetChildren() do
            if child:IsA("Tool") then
                return true
            end
        end
    end
    return false 
end

Thanks for any help guys and let me know if I need to clarify anything!