Finite\Loader\ArrayLoader::getCallbacksResolver PHP Method

    private function getCallbacksResolver()
    {
        $resolver = new OptionsResolver();
        $resolver->setDefaults(array('on' => array(), 'from' => array(), 'to' => array()));
        $resolver->setRequired(array('do'));
        $resolver->setAllowedTypes('on', array('string', 'array'));
        $resolver->setAllowedTypes('from', array('string', 'array'));
        $resolver->setAllowedTypes('to', array('string', 'array'));
        $toArrayNormalizer = function (Options $options, $value) {
            return (array) $value;
        };
        $resolver->setNormalizer('on', $toArrayNormalizer);
        $resolver->setNormalizer('from', $toArrayNormalizer);
        $resolver->setNormalizer('to', $toArrayNormalizer);
        return $resolver;
    }