code: private static boolean isPeerChanged(Change change, ChangedIssue issue) {
      Optional<User> assignee = issue.getAssignee();
      return !assignee.isPresent() || !change.isAuthorLogin(assignee.get().getLogin());
    }
docs: Is the author of the change the assignee of the specified issue?
  If not, it means the issue has been changed by a peer of the author of the change.