Some code

somecode.php

<?php

namespace felipecwb\Something;

interface Storage {
    public function persist($data);
    public function delete($data);
    public function getById($id);
}


class RelationalStorage implements Storage {
    // implements
}
class GraphStorage implements Storage {
    // implements
}
class FileStorage implements Storage {
    // implements
}


class ProductStorageService implements Storage {

    private $api;

    public function __construct(Storage $api) {
        $this->api = $api;
    }

    public function persist(Product $product) {
        $this->api->persist($product);
    }

    public function delete(Product $product) {
        $this->api->delete($product);
    }

    public function getById($id) {
        $this->api->getById($id);
    }

}