private static function _parse_experiments() { if (empty(self::$_experiments) && defined('UPFRONT_EXPERIMENTS_ON') && UPFRONT_EXPERIMENTS_ON) { $level = UPFRONT_EXPERIMENTS_ON; if (in_array($level, array(1, '1', true), true)) { self::$_experiments = self::LEVEL_DEFAULT; } else { self::$_experiments = $level; } } }