marcelo.php

<?php

require 'vendor/autoload.php';

$template = [
	'keys[]' => new mef\Validation\TypedArray(
		new mef\Validation\SanitizationChain(
			[
				new mef\Validation\DefaultValue('false'),
				new mef\Validation\Boolean()
			]
		),
		new mef\Validation\Integer())
	];

$data = [
	'keys' => [
		['1' => 'false', '2' => 'true'],
		['3' => 'false', '4' => 'true', '5' => null],
	]
	];

$sanitizer = new mef\Validation\Template($template);

$output = $sanitizer->sanitize($data);

var_dump($output);