Question

ValueError: Key() must have an even number of positional arguments.

When I try:

class MyStorage(ndb.Model):
 my_attr = ndb.StringProperty()

 my = MyStorage(parent=ndb.Key('mylist'), key_name='myattr', my_attr = 'hello')

What am I doing wrong?

My aim is to store a few MyStorage entities under a parent entity with key ‘mylist’. I don’t want to attach anything to the parent itself, and neither have I instantiated it, but from the docs I didn’t get the impression that was necessary.

How do I persist MyStorage entities the way I describe above correctly?

Answer 1

The ndb.Key() constructuctor expects pairs of kind and id values, not one string:

ndb.Key(model1, id1, model2, id2, ..)

The pairs can be specified in different ways, or you need to provide a urlsafe argument (which is a websafe-base64-encoded serialized reference).