### Question:
Optimizer { static Matcher convertEmptyCharClassToFalse(Matcher matcher) { if (matcher instanceof CharClassMatcher) { return matcher.<CharClassMatcher>as().set().isEmpty() ? FalseMatcher.INSTANCE : matcher; } return matcher; } private  Optimizer();   }### Answer:
@Test public void convertEmptyCharClassToFalse() { Matcher input = new CharClassMatcher(AsciiSet.none()); Matcher expected = FalseMatcher.INSTANCE; Assertions.assertEquals(expected, Optimizer.convertEmptyCharClassToFalse(input)); }