mongoengine.errors.FieldDoesNotExist: The fields do not exist on the document

[Pacheco95]

Why this isn't working? If I change EnumField to be StringField it works, so the problem probably is marshmallow_enum

from enum import Enum
from marshmallow_enum import EnumField
from mongoengine import Document


class MyEnum(Enum):
    ENUM_VAL = "ENUM_VAL"


class MyModel(Document):
    type = EnumField(MyEnum, required=True)


MyModel(type=MyEnum.ENUM_VAL)

Traceback (most recent call last):
  File "<redatcted>/test.py", line 14, in <module>
    MyModel(type=MyEnum.ENUM_VAL)
  File "<redatcted>/venv/lib/python3.8/site-packages/mongoengine/base/document.py", line 92, in __init__
    raise FieldDoesNotExist(msg)
mongoengine.errors.FieldDoesNotExist: The fields "{'type'}" do not exist on the document "MyModel"