code: @Override
      public void setSetting(String setting) throws CDKException {
          if (setting.equals("true") || setting.equals("false")) {
              this.setting = setting;
          } else if (setting.equals("yes") || setting.equals("y")) {
              this.setting = "true";
          } else if (setting.equals("no") || setting.equals("n")) {
              this.setting = "false";
          } else {
              throw new CDKException("Setting " + setting + " is not a boolean.");
          }
      }
docs: Sets the setting for a certain question. The setting
  is a boolean, and it accepts only "true" and "false".