code: def DeletePendingNotification(self, timestamp):
      
      shown_notifications = self.Get(self.Schema.SHOWN_NOTIFICATIONS)
      if not shown_notifications:
        shown_notifications = self.Schema.SHOWN_NOTIFICATIONS()
  
      pending = self.Get(self.Schema.PENDING_NOTIFICATIONS)
      if not pending:
        return
  
      # Remove all notifications with the given timestamp from pending
      # and add them to the shown notifications.
      delete_count = 0
      for idx in reversed(range(0, len(pending))):
        if pending[idx].timestamp == timestamp:
          shown_notifications.Append(pending[idx])
          pending.Pop(idx)
          delete_count += 1
  
      if delete_count > 1:
        raise UniqueKeyError("Multiple notifications at %s" % timestamp)
  
      self.Set(self.Schema.PENDING_NOTIFICATIONS, pending)
      self.Set(self.Schema.SHOWN_NOTIFICATIONS, shown_notifications)
docs: Deletes the pending notification with the given timestamp.
  
      Args:
        timestamp: The timestamp of the notification. Assumed to be unique.
  
      Raises:
        UniqueKeyError: Raised if multiple notifications have the timestamp.