How can I serialize a MongoDB ObjectId with Marshmallow?

Question

I\'m building and API on top of Flask using marshmallow and mongoengine. When I make a call and an ID is supposed to be serialized I receive the following error:

Answer 1

marshmallow-mongoengine does this:

Marshmallow-Mongoengine is about bringing together a Mongoengine Document with a Marshmallow Schema.

import marshmallow_mongoengine as ma


class ProcessSchema(ma.ModelSchema):
    class Meta:
        model = Process

It has an ObjectId field that serializes/deserializes ObjectIds.