php class error handling
<pre><code>class Foo {
    private $_bar;

    public function getBar() {
        return $this-&gt;_bar;
    }
}
$b = new Foo(); 
$b-&gt;xxx(); //xxx is an udefined method.
</code></pre>

<p>How to enhance the following class to throw a notice if undefined methods is called? </p>
