public void UTCID01() => Assert.AreEqual(29, Utilities.DaysInMonth(2016, 2));
 public void UTCID08() => Assert.AreEqual(0, Utilities.DaysInMonth(2016, 13));
 public void UTCID07() => Assert.AreEqual(28, Utilities.DaysInMonth(2100, 02));
 public void UTCID06() => Assert.AreEqual(31, Utilities.DaysInMonth(2017, 12));
 public void UTCID05() => Assert.AreEqual(30, Utilities.DaysInMonth(2017, 11));
 public void UTCID04() => Assert.AreEqual(28, Utilities.DaysInMonth(2017, 02));