type object 'XXX' has no attribute '_fields'

[jabbawockeez]

I'm using DocumentSerializer to do the job, and I got this message when I was trying to serialize a mongo model object:

/usr/local/lib/python3.6/site-packages/rest_framework_mongoengine/serializers.py in __repr__(self)
    797
    798     def __repr__(self):
--> 799         return serializer_repr(self, indent=1)
    800
    801

/usr/local/lib/python3.6/site-packages/rest_framework_mongoengine/repr.py in serializer_repr(serializer, indent, force_many)
    105         fields = force_many.fields
    106     else:
--> 107         fields = serializer.fields
    108
    109     for field_name, field in fields.items()

/usr/local/lib64/python3.6/site-packages/django/utils/functional.py in __get__(self, instance, cls)
     46         if instance is None:
     47             return self
---> 48         res = instance.__dict__[self.name] = self.func(instance)
     49         return res
     50

/usr/local/lib/python3.6/site-packages/rest_framework/serializers.py in fields(self)
    361         # even if Django's app-loading stage has not yet run.
    362         fields = BindingDict(self)
--> 363         for key, value in self.get_fields().items():
    364             fields[key] = value
    365         return fields

/usr/local/lib/python3.6/site-packages/rest_framework_mongoengine/serializers.py in get_fields(self)
    324
    325         # Retrieve metadata about fields & relationships on the model class.
--> 326         self.field_info = get_field_info(model)
    327         field_names = self.get_field_names(declared_fields, self.field_info)
    328         # Determine any extra field arguments and hidden fields that

/usr/local/lib/python3.6/site-packages/rest_framework_mongoengine/utils.py in get_field_info(model)
     64         pk = None
     65     else:
---> 66         pk = model._fields[model._meta['id_field']]
     67
     68     # Deal with regular fields.

AttributeError: type object 'XXX' has no attribute '_fields'

then I ran the django shell and realized the model has no "_fields" attribute, how does this even work?
And by the way, my model is inherit from djongo's model

[uoxiu]

Can you send us the contents of the pip freeze?

[jabbawockeez]

Can you send us the contents of the pip freeze?

amqp==2.5.2
asgiref==3.2.7
backcall==0.1.0
billiard==3.6.3.0
bson==0.5.8
celery==4.4.2
certifi==2020.4.5.1
chardet==3.0.4
coreapi==2.3.3
coreschema==0.0.4
dataclasses==0.7
decorator==4.4.2
Django==3.0.6
django-cors-headers==3.3.0
django-debug-toolbar==2.2
django-filter==2.2.0
django-mongodb-engine==0.6.0
django-rest-framework-mongoengine==3.4.1
djangorestframework==3.11.0
djangotoolbox==1.8.0
djongo==1.3.2
drf-generator==0.0.5
drf-generators==0.5.0
drf-yasg==1.17.1
flake8==3.8.3
idna==2.9
importlib-metadata==1.6.1
inflection==0.4.0
ipython==7.14.0
ipython-genutils==0.2.0
itypes==1.2.0
jedi==0.17.0
Jinja2==2.11.2
kombu==4.6.8
MarkupSafe==1.1.1
mccabe==0.6.1
mongoengine==0.20.0
openapi-codec==1.3.2
packaging==20.4
parso==0.7.0
pexpect==4.8.0
pickleshare==0.7.5
prompt-toolkit==3.0.5
ptyprocess==0.6.0
pycodestyle==2.6.0
pyflakes==2.2.0
Pygments==2.6.1
pymongo==3.10.1
PyMySQL==0.9.3
pyparsing==2.4.7
python-dateutil==2.8.1
pytz==2020.1
redis==3.5.0
requests==2.23.0
rest-meets-djongo==0.0.13
ruamel.yaml==0.16.10
ruamel.yaml.clib==0.2.0
simplejson==3.17.0
six==1.15.0
SQLAlchemy==1.3.16
sqlparse==0.2.4
traitlets==4.3.3
uritemplate==3.0.1
urllib3==1.25.9
vine==1.3.0
wcwidth==0.1.9
yapf==0.30.0
zipp==3.1.0