### Question:
CustomFunction extends Function implements IFunction { @Nonnull public String getContent() { return this.content.toString(); } private  CustomFunction(@Nonnull String name,
                           @Nonnull List<String> parameterNames,
                           @Nonnull Expression content,
                           @Nullable String description); private  CustomFunction(@Nonnull String name,
                           @Nonnull List<String> parameterNames,
                           @Nonnull String content,
                           @Nullable String description); @Override int getMinParameters(); @Override int getMaxParameters(); @Override Generic substitute(@Nonnull Variable variable, @Nonnull Generic generic); @Override Generic numeric(); @Override Generic expand(); @Override Generic elementary(); @Override Generic factorize(); @Override Generic selfExpand(); @Override void copy(@Nonnull MathEntity mathEntity); @Override Generic selfElementary(); @Override Generic selfSimplify(); @Override Generic selfNumeric(); @Override Generic antiDerivative(@Nonnull Variable variable); @Override Generic antiDerivative(int n); @Nonnull @Override Generic derivative(@Nonnull Variable variable); @Override Generic derivative(int n); @Nonnull String getContent(); @Nullable String getDescription(); @Nonnull List<String> getParameterNames(); @Nonnull @Override CustomFunction newInstance();  }### Answer:
@Test public void testNumbersAreReadInBinMode() throws Exception { final JsclMathEngine me = JsclMathEngine.getInstance(); me.setNumeralBase(NumeralBase.bin); final CustomFunction f = new CustomFunction.Builder("test", asList("x", "y"), "2000*x-0.001*y").create(); assertEquals(NumeralBase.bin, me.getNumeralBase()); me.setNumeralBase(NumeralBase.dec); assertEquals("2000*x-0.001*y", f.getContent()); }