code: @Override
    public void setNodeCountry(String nodeCountry) throws IllegalArgumentException {
      if (nodeCountry == null) {
        throw new IllegalArgumentException("nodeCountry must not be null");
      }
      if (!nodeCountry.trim().matches(pattern)) {
        throw new IllegalArgumentException(nodeCountry + " is not a valid country code");
      }
      this.nodeCountry = prepareForAssignment(this.nodeCountry, nodeCountry.trim().toUpperCase());
    }
docs: {@inheritDoc}