private static void handleMergeOperator(Object parsed) {
    handleMergeOperator(parsed, Collections.newSetFromMap(new IdentityHashMap<>()));
  }
Utility for parsing YAML files into java objects using snakeyaml to handle aliases and anchors and jackson to map
into java model objects.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/YAML.java