code: public void add(CommandOption option) {
  
  		Assert.notNull(option, "Missing command line option");
  
  		CommandOption found = find(option);
  		Assert.isNull(found, "Given option: " + option + " overlaps with: " + found);
  
  		options.add(option);
  	}
docs: Adds new option and checks if option overlaps with existing options
  
  @param option to be added
  @throws IllegalArgumentException in case option overlaps with existing options by name, long name or setting