Can't save models where a datetime field is nested in a dict/list

[Jean-Tiare Le Bigot]

List and dicts are persisted as JSON string in DynamoDB. Unfortunately datetime object can not be JSON (de-)serialized thus causing "save" to fail with an exception.

[Éric Araujo]

This can also be thought of as “deep schema”, i.e. the need for a way to define types or converters for items in list, set and dict fields.