Modified Laravel Vendor files issue

I had modified a vendor file of Laravel placed at /vendor/laravel/framework/src/Illuminate/Auth/Guard.php but it will be overwritted upon updating Laravel.

I'm looking for a way tu put the code somewhere in my /app to prevent the overwrite.

The function modified is
public function UpdateSession() { $this->session->set('type', $type); //==> Set Client Type }

Also there's a new function on the file:

public function type() { return $this->session->get('type'); //==> Get Client Type }

Codes above are called in many places in my application.

Any idea?

via Chebli Mohamed