Session handler issue

index.php

<?php

function session_handler_open($save_path, $session_name) {
    return TRUE;
}

function session_handler_close() {
    return TRUE;
}

function session_handler_store($key, $data) {
    return TRUE;
}

function session_handler_fetch($key) {
    return [];
}

function session_handler_delete($key) {
    return TRUE;
}

function session_handler_gc($timeout) {
    return TRUE;
}

session_set_save_handler('session_handler_open', 'session_handler_close', 'session_handler_fetch', 'session_handler_store', 'session_handler_delete', 'session_handler_gc');

session_start();