protected static function customHelper(&$context, $vars, $raw, $nosep, $subExp = false) {
        if (count($vars[0]) > 1) {
            return;
        }

        if (!isset($context['helpers'][$vars[0][0]])) {
            if ($subExp) {
                if ($vars[0][0] == 'lookup') {
                    return static::compileLookup($context, $vars, $raw, true);
                }
            }
            return;
        }

        $fn = $raw ? 'raw' : $context['ops']['enc'];
        $ch = array_shift($vars);
        $v = static::getVariableNames($context, $vars);
        static::addUsageCount($context, 'helpers', $ch[0]);
        $sep = $nosep ? '' : $context['ops']['seperator'];

        return $sep . static::getFuncName($context, 'hbch', "$ch[0] " . implode(' ', $v[1])) . "\$cx, '$ch[0]', {$v[0]}, '$fn', \$in)$sep";
    }