gistfile1.php

<?php

class Father {
    private   $fProperty;

    public function setProp($fProperty) {
        $this->fProperty = $fProperty;

        return $this;
    }

}

class Child extends Father {

}


$father =  new Father();
$father->setProp('fatherprop');

var_dump($father);



$child =  new Child();

var_dump($child);

$child->setProp('chprop');
var_dump($child);

?>