public function comment()
 {
     $comment = $this->changeset->getComment();
     if ($comment) {
         return $comment->fetchFollowUp();
     }
 }
 public function exportFullHistory(SimpleXMLElement $artifact_xml, Tracker_Artifact_Changeset $changeset)
 {
     $changeset_xml = $artifact_xml->addChild('changeset');
     $this->user_xml_exporter->exportUserByUserId($changeset->getSubmittedBy(), $changeset_xml, 'submitted_by');
     $submitted_on = $changeset_xml->addChild('submitted_on', date('c', $changeset->getSubmittedOn()));
     $submitted_on->addAttribute('format', 'ISO8601');
     $comments_node = $changeset_xml->addChild('comments');
     if ($changeset->getComment()) {
         $changeset->getComment()->exportToXML($comments_node);
     }
     $this->values_exporter->exportChangedFields($artifact_xml, $changeset_xml, $changeset->getArtifact(), $changeset->getValues());
 }