docs: public static YamlSequence asSequence(YamlNode node) {
          if (node != null && !(node instanceof YamlSequence)) {
              String nodeName = node.nodeName();
              throw new YamlException(String.format("Child %s is not a sequence, it's actual type is %s",
                      nodeName, node.getClass()));
          }
  
          return (YamlSequence) node;
      }