code: public function createTopic(string $name): string
      {
          $res = $this->sns->createTopic(
              [
                  'Name' => $name,
              ]
          );
  
          return $res['TopicArn'];
      }
docs: Create a topic.
  
  @param string $name Topic name
  
  @return string The topic ARN
  
  @deprecated use SnsClient directly to subscribe