public void Subscribe() { // get by name var list = ListsApi.GetByName("Test"); Assert.IsNotNull(list); var subscriber = new Subscriber("*****@*****.**") { FirstName = "Test", LastName = "User" }; subscriber .SetField("TESTFIELD", "test") .AddInterest("Group1", "Value1"); //subscriber.AddInterest("Group1", "Value2"); ListsApi.Subscribe(list.Id, subscriber); //var g = list.InterestGroups; }