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 absFunctionNumber() {
        FunctionTestUtil.assertResult(absFunction.invoke(valueOf(10)), valueOf(10));
        FunctionTestUtil.assertResult(absFunction.invoke(valueOf(-10)), valueOf(10));
        FunctionTestUtil.assertResultError(absFunction.invoke((BigDecimal) null), InvalidParametersEvent.class);
    }