public static ValidateTarget <bool?> NotTrue([ValidatedNotNull] this ValidateTarget <bool?> target, Func <string> getErrorMessage = null)
        {
            if (target.Value.HasValue && target.Value.Value)
            {
                ExceptionFactory.ThrowException(target.Traits.GenericFailureExceptionType, getErrorMessage != null ? getErrorMessage.Invoke() : ErrorMessageFactory.ShouldBeTrue(target));
            }

            return(target);
        }