SunsetHigh.PanelGroupSorter.nullCheck C# (CSharp) Method

        private static void nullCheck()
        {
            if (panelGroups == null)
                panelGroups = new HashSet<PanelGroup>();
            if (activeGroups == null)
                activeGroups = new HashSet<PanelGroup>();
            if (activePanels == null)
                activePanels = new HashSet<Panel>();
        }