@Override
    public Map<String, Object> load(String configKey) {
        if (targetFilePath != null) {
            try {
                Map<String, Object> raw = (Map<String, Object>) Utils.readYamlFile(targetFilePath);
                if (raw != null) {
                    return (Map<String, Object>) raw.get(configKey);
                }
            } catch (Exception e) {
                LOG.error("Failed to load from file {}", targetFilePath);
            }
        }
        return null;
    }
@Test
    public void testFileNotThere() {
        Config conf = new Config();
        conf.put(DaemonConfig.SCHEDULER_CONFIG_LOADER_URI, FILE_SCHEME_PREFIX + "/file/not/exist/");
        FileConfigLoader testLoader = new FileConfigLoader(conf);
        Map<String, Object> result = testLoader.load(DaemonConfig.MULTITENANT_SCHEDULER_USER_POOLS);
        assertNull(result, "Unexpectedly returned a map");
    }