code: public OptionsBuilder configurationFormat(String configurationFormat){
  		String aux = configurationFormat.toLowerCase().trim();
  		if(aux.equals("yaml") || aux.equals("json")){
  			aux = "yml";
  		}
  		if (aux.equals("xml") || aux.equals("yml")) {
  			options.put(Options.CONFIGURATION_FILE_FORMAT, aux);
  		} else {
  			throw new IllegalArgumentException("The configuration format "+aux+" is not supported");
  		}
  		return this;
  	}
docs: Sets the configuration format (xml or yml)
  
  @param configurationFormat
  configuration format (file extension)
  
  @return updated OptionBuilder instance
  
  @see Options#CONFIGURATION_FILE_FORMAT