def current_label_revision
      return nil if my_messages.empty?
      @current_label_revision ||= begin
        date = current_label_date
        comment_for_current_label = my_messages.find { |message| message["date"] == date } ||
                                    my_messages.last
        comment_for_current_label["_revision_number"]
      end
    end
def current_label_revision
      return nil if my_messages.empty?
      @current_label_revision ||= begin
        date = current_label_date
        comment_for_current_label = my_messages.find { |message| message["date"] == date } ||
                                    my_messages.last
        comment_for_current_label["_revision_number"]
      end
    end
unfortunately, the revision is not a field in the label json.
 however, we can match the label timestamp w/ one of our comment timestamps,
 then grab the comment's revision.