Assuming you're using the ULX Admin Mod (I guess that would be why you're here), I recommend not using your current layout:
customCheck = function(ply) return
table.HasValue({"superadmin", "admin", "donator"}, ply:GetNWString("usergroup"))
end,
CustomCheckFailMsg = "You don't have the required rank to complete this action!",
Instead replace it with this:
customCheck = function(ply) return
ply:GetUserGroup() == "donator" or ply:IsAdmin() or ply:IsSuperAdmin() end,
CustomCheckFailMsg = "You don't have the required rank to complete this action!",
Much easier to lay out, AND it calls for the ULX Groups

P.S. If you want to add more groups, the just use
ply:GetUserGroup() == "groupname"
And don't forget the "or" when using multiple groups!