Drupal Dependencies injection in a custom class/service

book.services.yml

services:
  book.manager:
    class: Drupal\book\BookManager
    arguments: ['@entity.manager', '@string_translation', '@config.factory', '@book.outline_storage', '@renderer']

BookManager.php

<?php

namespace Drupal\book;

use Drupal\Core\Entity\EntityManagerInterface;
use Drupal\Core\Render\RendererInterface;
use Drupal\Core\StringTranslation\TranslationInterface;
use Drupal\Core\Config\ConfigFactoryInterface;
...

/**
 * Defines a book manager.
 */
class BookManager implements BookManagerInterface {

  /**
   * Entity manager Service Object.
   *
   * @var \Drupal\Core\Entity\EntityManagerInterface
   */
  protected $entityManager;

  /**
   * Config Factory Service Object.
   *
   * @var \Drupal\Core\Config\ConfigFactoryInterface
   */
  protected $configFactory;

  /**
   * Books Array.
   *
   * @var array
   */
  protected $books;

  /**
   * Book outline storage.
   *
   * @var \Drupal\book\BookOutlineStorageInterface
   */
  protected $bookOutlineStorage;

  /**
   * Stores flattened book trees.
   *
   * @var array
   */
  protected $bookTreeFlattened;

  /**
   * The renderer.
   *
   * @var \Drupal\Core\Render\RendererInterface
   */
  protected $renderer;

  /**
   * Constructs a BookManager object.
   */
  public function __construct(EntityManagerInterface $entity_manager, TranslationInterface $translation, ConfigFactoryInterface $config_factory, BookOutlineStorageInterface $book_outline_storage, RendererInterface $renderer) {
    $this->entityManager = $entity_manager;
    $this->stringTranslation = $translation;
    $this->configFactory = $config_factory;
    $this->bookOutlineStorage = $book_outline_storage;
    $this->renderer = $renderer;
  }

  ...

}