code: public ConfigurationPropertyName append(String elementValue) {
  		if (elementValue == null) {
  			return this;
  		}
  		Elements additionalElements = probablySingleElementOf(elementValue);
  		return new ConfigurationPropertyName(this.elements.append(additionalElements));
  	}
docs: Create a new {@link ConfigurationPropertyName} by appending the given element
  value.
  @param elementValue the single element value to append
  @return a new {@link ConfigurationPropertyName}
  @throws InvalidConfigurationPropertyNameException if elementValue is not valid