public void checkIsDuplicateAlias(List<String> aliases) {
        Set<String> aliasSet = new HashSet<>(aliases);
        if (aliasSet.size() < aliases.size()) {
            throw new SectionAliasDuplicateException();
        }
    }
@Test
    void 요청에_중복된_별칭이_있다면_에러를_반환한다() {
        // given
        List<String> aliases = Arrays.asList(null, "Alias1", "Alias1");

        // when
        // then
        assertThrows(
                SectionAliasDuplicateException.class,
                () -> createSectionService.checkIsDuplicateAlias(aliases));
    }