public void WithinPeriod()
 {
     Assert.True(testPeriod1.WithinPeriod(DateTime.Parse("2018-07-01")));
     Assert.True(testPeriod1.WithinPeriod(DateTime.Parse("2018-12-31")));
     Assert.False(testPeriod1.WithinPeriod(DateTime.Parse("2018-12-25")));
     Assert.False(testPeriod1.WithinPeriod(DateTime.Parse("2018-06-30")));
 }