class Assignee(EmbeddedDocument):
    id = ObjectIdField(primary_key=True)
    assignee_email = EmailField(required=True)
    assignee_first_name = StringField(required=True)
    assignee_last_name = StringField()
    assignee_time = DateTimeField(required=True, default=datetime.datetime.utcnow)
    user = ReferenceField('MongoUser', required=True)
    user_id = ObjectIdField(required=True)

class MongoUser(Document):
    email = EmailField(required=True, unique=True)
    password = StringField(required=True)
    first_name = StringField(required=True)
    last_name = StringField()
    assignees= EmbeddedDocumentListField(Assignee)

class MongoUserSerializer(DocumentSerializer):
    assignees = AssigneeSerializer(many=True)
    class Meta:
        model = MongoUser
        fields = ('id', 'email', 'first_name', 'last_name', 'assignees')
        depth = 2

class AssigneeSerializer(EmbeddedDocumentSerializer):
    class Meta:
        model = Assignee
        fields = ('assignee_first_name', 'assignee_last_name', 'user')
        depth = 0

class AssigneeSerializer(EmbeddedDocumentSerializer):
    class Meta:
        model = Assignee
        fields = ('assignee_first_name', 'assignee_last_name', 'user_id')
        depth = 0

fields = ('assignee_first_name', 'assignee_last_name', 'user_id')