private static void Main()
    {
        // "Read" an excel document and set properties in this class
        var excelDoc = new ExcelDocument
        {
            SomeValue      = "original Value",
            SomeOtherValue = "original value"
        };
        // Instantiate the classes above so they can use the document without re-reading it
        var class1 = new ClassOne(excelDoc);
        var class2 = new ClassTwo(excelDoc);

        // Output the original values of our document
        Console.WriteLine(excelDoc);
        // Have each class do their operations on the document
        class1.DoSomethingWithExcelData();
        class2.DoSomethingWithExcelData();
        // Output the values again to show how the two independent classes
        // manipulated the same document (and without reading it)
        Console.WriteLine(excelDoc);
        GetKeyFromUser("\nDone! Press any key to exit...");
    }