Can't declare injection method in base class

example-20.php

<?php

namespace Application {
    abstract class Page {
        public $blocks;
        public function addBlock(Block $block){
            $this->blocks[] = $block;
        }
    }
    class FancyPage extends Page{
    }
    class BoringPage extends Page{
    }
    interface Block {
    }
}

namespace DifferentNs {
    class BlockOne implements \Application\Block {}
    class BlockTwo implements \Application\Block {}        
}

namespace {
    // bootstrap
    include 'zf2bootstrap' . ((stream_resolve_include_path('zf2bootstrap.php')) ? '.php' : '.dist.php');

    $di = new Zend\Di\Di;
    $di->configure(new Zend\Di\Configuration(array(
        'definition' => array(
            'class' => array(
                'Application\Page' => array(
                    'addBlock' => array(
                        'block' => array(
                        	'type' => 'Application\Block',
                        	'required' => true
                        ),
                    ),
                ),
            ),
        ),
        'instance' => array(
            'Application\FancyPage' => array(
                'injections' => array(
                    'DifferentNs\BlockOne',
                    'DifferentNs\BlockTwo'
                ),
            ),
            'Application\BoringPage' =>array(
                'injections' => array(
                    'DifferentNs\BlockOne',
                ),
            ),
        )
    )));
    $fancyPage = $di->get('Application\FancyPage');
    $boringPage = $di->get('Application\BoringPage');

    // expression to test
    $works = (
        $fancyPage->blocks[0] instanceof DifferentNs\BlockOne
        && $fancyPage->blocks[1] instanceof DifferentNs\BlockTwo
        && $boringPage->blocks[0] instanceof DifferentNs\BlockOne
        && !isset($boringPage->blocks[1])
    );

    // display result
    echo (($works) ? 'It works!' : 'It DOES NOT work!') . PHP_EOL;
}