code: def add_property_orders(query_proto, *orders):
    
    for order in orders:
      proto = query_proto.order.add()
      if order[0] == '-':
        order = order[1:]
        proto.direction = query_pb2.PropertyOrder.DESCENDING
      else:
        proto.direction = query_pb2.PropertyOrder.ASCENDING
      proto.property.name = order
docs: Add ordering constraint for the given datastore.Query proto message.
  
    Args:
      query_proto: datastore.Query proto message.
      orders: list of propertype name string, default to ascending
      order and set descending if prefixed by '-'.
  
    Usage:
      >>> add_property_orders(query_proto, 'foo')  # sort by foo asc
      >>> add_property_orders(query_proto, '-bar')  # sort by bar desc