code: protected function buildRecipientsField($identities)
      {
          if (null === $identities) {
              return [];
          }
  
          if (is_string($identities)) {
              return [
                  [
                      'Email' => $identities,
                  ],
              ];
          }
  
          $identities = (array) $identities;
  
          $recipients = [];
          foreach ($identities as $identity) {
              if (is_string($identity)) {
                  $recipients[] = [
                      'Email' => $identity,
                  ];
  
                  continue;
              }
  
              $recipient = [
                  'Email' => $identity->getEmail(),
              ];
  
              if (null !== $name = $identity->getName()) {
                  $recipient['Name'] = $name;
              }
  
              $recipients[] = $recipient;
          }
  
          return $recipients;
      }
docs: @param IdentityInterface[]|string $identities
  
  @return array