docs: def WriteUserNotification(self, notification, cursor=None):
      """Writes a notification for a given user."""
      # Copy the notification to ensure we don't modify the source object.
      args = {
          "username_hash":
              mysql_utils.Hash(notification.username),
          "notification_state":
              int(notification.state),
          "notification":
              notification.SerializeToString(),
      }
      query = "INSERT INTO user_notification {columns} VALUES {values}".format(
          columns=mysql_utils.Columns(args),
          values=mysql_utils.NamedPlaceholders(args))
      try:
        cursor.execute(query, args)
      except MySQLdb.IntegrityError:
        raise db.UnknownGRRUserError(notification.username)