How to use the webdriver.firefox.profile function in webdriver

var deprecationNotice = function(propertyName, newSettingName) {
      ErrorHandler.logWarning('DEPRECATION NOTICE: Property ' + propertyName + ' is deprecated since v0.5. Please' +
        ' use the "cli_args" object on the "selenium" property to define "' + newSettingName + '". E.g.:');
      var demoObj = '{\n' +
        '  "cli_args": {\n' +
        '    "'+ Logger.colors.yellow(newSettingName) +'": ""\n' +
        '  }\n' +
        '}';

      console.log(demoObj, '\n');
    };

    if (this.test_settings.firefox_profile) {
      deprecationNotice('firefox_profile', 'webdriver.firefox.profile');
      this.settings.selenium.cli_args['webdriver.firefox.profile'] = this.test_settings.firefox_profile;
    }
    if (this.test_settings.chrome_driver) {
      deprecationNotice('chrome_driver', 'webdriver.chrome.driver');
      this.settings.selenium.cli_args['webdriver.chrome.driver'] = this.test_settings.chrome_driver;
    }
    if (this.test_settings.ie_driver) {
      deprecationNotice('ie_driver', 'webdriver.ie.driver');
      this.settings.selenium.cli_args['webdriver.ie.driver'] = this.test_settings.ie_driver;
    }

    return this;
  },