private function formatShorthandRecipients($payload)
{
if (isset($payload['content']['from'])) {
$payload['content']['from'] = $this->toAddressObject($payload['content']['from']);
}
for ($i = 0; $i < count($payload['recipients']); ++$i) {
$payload['recipients'][$i]['address'] = $this->toAddressObject($payload['recipients'][$i]['address']);
}
return $payload;
}