Method addIncludePath

/**
 * Add a directory where Cache should search for handlers. You may either pass a string or an array of directories.
 *
 * @param   array|string  $path  A path to search.
 *
 * @return  array   An array with directory elements
 *
 * @since   1.7.0
 */
public static function addIncludePath($path = '')
{
    static $paths;
    if (!isset($paths)) {
        $paths = array();
    }
    if (!empty($path) && !\in_array($path, $paths)) {
        array_unshift($paths, Path::clean($path));
    }
    return $paths;
}