Laravel 4: Getter and Setter Methods

Question

I tried to get Getter & Setter Methods work (from Laravel 3 in Laravel 4)

but display Error.

is there any work around here?

they are very useful in password case:

public function set_password($password)
{
    $this->set_attribute('hashed_password', Hash::make($password));
}

http://three.laravel.com/docs/database/eloquent