public Optional<Issue> validateExtensionVersion(String version) {
        return Observation.createNotStarted("ExtensionValidator#validateExtensionVersion", observations).observe(() -> {
            var issues = new ArrayList<Issue>();
            checkVersion(version, issues);
            return issues.isEmpty()
                    ? Optional.empty()
                    : Optional.of(issues.get(0));
        });
    }
@Test
    public void testInvalidVersion1() {
        var issue = validator.validateExtensionVersion("latest");
        assertThat(issue).isPresent();
        assertThat(issue.get())
                .isEqualTo(new ExtensionValidator.Issue("The version string 'latest' is reserved."));
    }