code: public function api($apiName = null)
      {
          /** @var Repository $repo */
          $repo = $this->container->make(Repository::class);
  
          return $repo->createApi($apiName ?: $this->defaultApi());
      }
docs: Get an API by name.
  
  @param string|null $apiName
  @return Api
  @throws RuntimeException
  if the API name is invalid.