/**
  * Return the dates attribute.
  *
  * @param  StreamInterface $stream
  * @return string
  */
 public function parse(StreamInterface $stream)
 {
     $dates = [];
     $dates[] = "'created_at'";
     $dates[] = "'updated_at'";
     /* @var AssignmentInterface $assignment */
     foreach ($stream->getDateAssignments() as $assignment) {
         $dates[] = "'{$assignment->getFieldSlug()}'";
     }
     if ($stream->isTrashable()) {
         $dates[] = "'deleted_at'";
     }
     return "[" . implode(', ', $dates) . "]";
 }