code: function defaultOptions(options) {
  	options = extend({}, pa11y.defaults, options);
  	options.ignore = options.ignore.map(ignored => ignored.toLowerCase());
  	if (!options.includeNotices) {
  		options.ignore.push('notice');
  	}
  	if (!options.includeWarnings) {
  		options.ignore.push('warning');
  	}
  	return options;
  }
docs: Default the passed in options using Pa11y's defaults.
  @private
  @param {Object} [options={}] - The options to apply defaults to.
  @returns {Object} Returns the defaulted options.