class DateTimeIso8601

class DateTimeIso8601 extends StringData implements DateTimeInterface {
  
  /**
   * {@inheritdoc}
   */
  public function getDateTime() {
    if ($this->value) {
      if (is_array($this->value)) {
        // Data of this type must always be stored in UTC.
        $datetime = DrupalDateTime::createFromArray($this->value, 'UTC');
      }
      else {
        // Data of this type must always be stored in UTC.
        $datetime = new DrupalDateTime($this->value, 'UTC');
      }
      return $datetime;
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function setDateTime(DrupalDateTime $dateTime, $notify = TRUE) {
    $this->value = $dateTime->format('c');
    // Notify the parent of any changes.
    if ($notify && isset($this->parent)) {
      $this->parent
        ->onChange($this->name);
    }
  }

}