in src/main/java/org/apache/sling/testing/mock/caconfig/ConfigurationPersistHelper.java [110:117]
private String getNestedConfigName(@NotNull String configName, @NotNull String key) {
String nestedKey = configName + "/" + key;
String nestedConfigName = configurationPersistenceStrategy.getConfigName(nestedKey, null);
if (nestedConfigName == null) {
throw new IllegalArgumentException("Nested configuration not supported for " + nestedKey);
}
return nestedConfigName;
}