protected function addClassToOptions($classToAdd, array $options = [])
	{
		$class = array_get($options, 'class', '');
		if (is_array($class))
		{
			$class[] = $classToAdd;
		} elseif ( ! empty($class))
		{
			$class .= ' ' . $classToAdd;
		} else
		{
			$class = $classToAdd;
		}
		array_set($options, 'class', $class);
		return $options;
	}