orm.json not supported

[fluffy-critter]

I have a model class like:

class User(orm.core.Entity):
    name = orm.PrimaryKey(str)
    profile = orm.Required(orm.json)

When I attempt to make use of this field, mypy fails to see orm.json as being equivalent to a dict, so I can neither call user.profile.copy() nor can I return user.profile as a dict directly.

[fluffy-critter]

Wait, right, orm.json could be something that isn't a dict. Never mind.