void Check(object obj, params object[] expected)
{
var data = Printing1.Flatten(obj);
var counter = 0;
foreach(var e in data.SelectMany(z=>z))
{
Assert.AreEqual(e.Key, expected[counter]);
Assert.AreEqual(e.Value, expected[counter + 1]);
counter += 2;
}
Assert.AreEqual(expected.Length, counter);
}
