public FEELFnResult<BigDecimal> invoke(@ParameterName( "n" ) BigDecimal number) {
        if ( number == null ) {
            return FEELFnResult.ofError(new InvalidParametersEvent(Severity.ERROR, "number", "cannot be null"));
        }
        return FEELFnResult.ofResult( number.abs() );
    }
@Test
    void absFunctionDuration() {
        FunctionTestUtil.assertResult(absFunction.invoke(Duration.ofSeconds(100, 50 )),
                Duration.ofSeconds(100, 50));
        FunctionTestUtil.assertResult(absFunction.invoke(Duration.ofSeconds(-100, 50 )),
                Duration.ofSeconds(100, -50));
        FunctionTestUtil.assertResult(absFunction.invoke(Duration.ofSeconds(100, -50 )),
                Duration.ofSeconds(100, -50));
        FunctionTestUtil.assertResult(absFunction.invoke(Duration.ofSeconds(-100, -50 )),
                Duration.ofSeconds(100, 50));
        FunctionTestUtil.assertResultError(absFunction.invoke((Duration)null),
                InvalidParametersEvent.class);
    }