public static IStructValue ExtractStructValue(IWorkshopTree value)
        {
            // Struct value.
            if (value is IStructValue structValue)
            {
                return(structValue);
            }

            // Empty array.
            var emptyArray = MakeEmptyArray(value);

            if (emptyArray != null)
            {
                return(emptyArray);
            }

            // Unknown
            throw new Exception(value.ToString() + " is not a valid struct value.");
        }