### Question:
Optimizer { static Matcher convertSingleCharClassToSeq(Matcher matcher) { if (matcher instanceof CharClassMatcher) { Optional<Character> opt = matcher.<CharClassMatcher>as().set().character(); if (opt.isPresent()) { return new CharSeqMatcher(opt.get()); } } return matcher; } private  Optimizer();   }### Answer:
@Test public void convertSingleCharClassToSeq() { Matcher input = new CharClassMatcher(AsciiSet.fromPattern("a")); Matcher expected = new CharSeqMatcher('a'); Assertions.assertEquals(expected, Optimizer.convertSingleCharClassToSeq(input)); }