public void TryCreateReturnsFalseForNonNullableTypeReturnsFalse()
 {
     NullableEnumConverter <int> .TryCreate(out _).ShouldBeFalse();
 }
 public void TryCreateReturnsFalseForNonEnumUnderlyingType()
 {
     NullableEnumConverter <int?> .TryCreate(out _).ShouldBeFalse();
 }
 public void TryCreateReturnsInstanceForEnumType()
 {
     NullableEnumConverter <DayOfWeek?> .TryCreate(out _).ShouldBeTrue();
 }