Получение даты начала и окончания объекта PHP DatePeriod?

Как получить дату начала и окончания объекта DatePeriod?

$today  = new \DateTime(date('Y-m-d')); // 2012-05-30
$period = new \DatePeriod($today, new \DateInterval('P1M'), 1);

$stats = new UsageStatistics($period);

class UsageStatistics
{

    protected $period, $sentEmailCount, $autoSentEmailCount;

    public function __construct(\DatePeriod $period)
    {
        $this->period = $period;

        // Current logged in user and email repository
        $user = $this->getUser();
        $repo = $this->getEmailRepository();

        // Get the start and end date for the given period
        $startDate = ...
        $endDate   = ...

        $result = $repo->getAllSentCount($user, $startDate, $endDate);

        // Assigning object properties
    }

    public function getSentEmailCount() { return $this->sentEmailCount; }

    public function getAutoSentEmailCount() { return $this->autoSentEmailCount; }
}