code: private static JsonNode findNestedNode(JsonNode jsonNode, String composedKey) {
          String[] jsonNodeKeys = splitKeyByFlatteningDots(composedKey);
          for (String jsonNodeKey : jsonNodeKeys) {
              jsonNode = jsonNode.get(unescapeEscapedDots(jsonNodeKey));
              if (jsonNode == null) {
                  return null;
              }
          }
          return jsonNode;
      }
docs: Given a json node, find a nested node using given composed key.
  
  @param jsonNode the parent json node
  @param composedKey a key combines multiple keys using flattening dots.
  Flattening dots are dot character '.' those are not preceded by slash '\'
  Each flattening dot represents a level with following key as field key in that level
  @return nested json node located using given composed key