Unhandled Error

Uncaught ErrorException (2) in
/var/www/9/phvli/sites/phvli.kapsi.fi/core/lib/database.php:177:

E_WARNING

The magic method Database::__wakeup() must have public visibility

ErrorException: The magic method Database::__wakeup() must have public visibility in /var/www/9/phvli/sites/phvli.kapsi.fi/core/lib/database.php:177
Stack trace:
#0 [internal function]: {closure}()
#1 {main}