code: private String parseErrorCodeFromContents(JsonNode jsonContents) {
          if (jsonContents == null || !jsonContents.has(errorCodeFieldName)) {
              return null;
          }
          String code = jsonContents.findValue(errorCodeFieldName).asText();
          int separator = code.lastIndexOf("#");
          return code.substring(separator + 1);
      }
docs: Attempt to parse the error code from the response content. Returns null if information is not
  present in the content. Codes are expected to be in the form <b>"typeName"</b> or
  <b>"prefix#typeName"</b> Examples : "AccessDeniedException", "com.ibm.cloud.objectstorage.dynamodb.v20111205#ProvisionedThroughputExceededException"