public void AddElement2Test()
{
Multiplicity<string> many = new Multiplicity<string>();
many.AddElement("1");
Assert.IsTrue(many.ElementExist("1"));
}
public void AddElement1Test()
{
Multiplicity<int> many = new Multiplicity<int>();
many.AddElement(1);
Assert.IsTrue(many.ElementExist(1));
}