code: private function setRecipients(array $recipients)
      {
          if (count($recipients) === 0) {
              throw new InvalidArgumentException('At least one recipient required');
          }
  
          $this->recipients = [];
          foreach ($recipients as $recipient) {
              $this->addRecipient($recipient);
          }
      }
docs: Sets/replaces list of recipients.
  
  @param string[] $recipients A list of phone numbers in the one of formats: "+71234567890" or "71234567890".
  
  @throws \InvalidArgumentException If one of recipients is not a string or format is invalid.