How to create a Schema containing a dict of nested Schema?

Hi. I’ve been digging around and couldn’t find the answer to this.

Say I’ve got a model like this:

class AlbumSchema(Schema):
    year = fields.Int()

class ArtistSchema(Schema):
    name = fields.Str()
    albums = ...

I want albums to be a dict of AlbumSchema, so that ArtistSchema serializes as

{ 'albums': { 'Hunky Dory': {'year': 1971},
              'The Man Who Sold the World': {'year': 1970}},
  'name': 'David Bowie'}

Naively, I would expect syntaxes like this to work:

fields.List(Schema)
fields.Dict(Schema)

or maybe

fields.List(fields.Nested(Schema))
fields.Dict(fields.Nested(Schema))

Serializing a list of Schema can be achieved through Nested(Schema, many=True), which I find less intuitive, and I don’t know about a dict of Schema.

Is there any way to do it? Or a good reason not to do it?

(Question also asked on SO.)

[lafrech]

class ArtistSchema(Schema):
    name = fields.Str()
    albums = fields.Dict(keys=fields.Str(), values=fields.Nested(AlbumSchema()))

[sloria]

This is released in version 3.0.0b5. Thanks everyone for your feedback!