I'm trying to override a method but I get an error, that the function could not be found.
Here's an example:

```
abstract class a {
    public function build(){
        $this._loadComponents();
        return $this;
    }

    abstract protected function _loadComponents();
}

class b extends a {
    protected function _loadComponents(){
        echo "test";
    }
}
$b = new B();
$b->build();

```

Results in: Fatal error: Call to undefined function

What am I doing wrong?