private Col1 GetConstructorProperties(int nr)
        {
            string GetExpressionPlus()
            {
                switch (Cfg.TypeName)
                {
                case "AreaUnit":
                    return(@"?.Replace('2', '²')");

                case "VolumeUnit":
                    return(@"?.Replace('3', '³')");

                default:
                    return(null);
                }
            }

            var expr = PropertyName.FirstLower() + GetExpressionPlus();

            if (nr == 1)
            {
                if (Related is null || !Related.IsPower2OrHigher)
                {
                    return(null);
                }
                var a = new[]
                {
                    new ConstructorParameterInfo("BaseUnit", Related.MyInfo.PowerOne.Unit.TypeName, null, "based on",
                                                 Flags1.NotNull,
                                                 property =>
                    {
                        property.AddRelatedUnitSourceAttribute(Target, RelatedUnitSourceUsage.DoNotUse, 0);
                    }),
                    new ConstructorParameterInfo(PropertyName, "string", expr, "name of unit",
                                                 Flags1.Optional | Flags1.DoNotAssignProperty | Flags1.DoNotCreateProperty)
                };
                var h         = new Col1(a);
                var powerChar = Ext.GetPowerSuffix(Related.MyInfo.Power);
                h.Writer2.WriteLine("unitName = unitName?.Trim();");
                h.Writer2.WriteLine(PropertyName + " = string.IsNullOrEmpty(unitName) ? baseUnit.UnitName + " + powerChar.CsEncode() + " : unitName;");
                return(h);
            }

            {
                var b = new[]
                {
                    new ConstructorParameterInfo(PropertyName, "string", expr, "name of unit",
                                                 Flags1.NormalizedString)
                };
                return(new Col1(b));
            }
        }