void MakeRequired(ToggleableModProxy mod)
        {
            var serializationString = mod.GetSerializationString();

            RequiredMods.AddWhenMissing(serializationString);
            OptionalMods.RemoveLocked(serializationString);
            mod.IsRequired = true;
        }
 bool OptionalAllAllowed() => OptionalMods.Contains(":all");