private static ArrayNode normalizeKeysInArray(final ArrayNode arrayNode) {
    final ArrayNode normalizedArray = JsonUtil.createEmptyArrayNode();
    arrayNode.forEach(
        value -> {
          if (value instanceof ObjectNode) {
            normalizedArray.add(normalizeKeys((ObjectNode) value));
          } else if (value instanceof ArrayNode) {
            normalizedArray.add(normalizeKeysInArray((ArrayNode) value));
          } else {
            normalizedArray.add(value);
          }
        });
    return normalizedArray;
  }
Converts the key to lowercase for easier lookup. This is useful in cases such as the
'genesis.json' file where all keys are assumed to be case insensitive.

@param key the key to be normalized
@return key in lower case.
config/src/main/java/org/hyperledger/besu/config/JsonUtil.java