Problem with exclude EmbeddedDocumentListField

Hey.

I have a problem with exclude EmbeddedDocumentListField from my queryset.
I have a following code:

from mongoengine import (
    Document, StringField, 
    EmbeddedDocumentListField, EmbeddedDocument
)

class Bar(Document):
   name = StringField(max_length=256)

class  Foo(EmbeddedDocument):
   name = StringField(max_length=256)
   arr = EmbeddedDocumentListField(Bar)

foo = Foo(name="f1")
foo.save()

When I exclude EmbeddedDocumentListField, I get:

>>> f = Foo.objects.all().exclude('arr')[0]
>>> f.to_json()
'{"_id": {"$oid": "5c0ef4280d068742e9ddcec5"}, "name": "a", "arr": []}

but when I exclude normal field like name I get :

>>> f = Foo.objects.all().exclude('name')[0]
>>> f.to_json()
'{"_id": {"$oid": "5c0ef4280d068742e9ddcec5"}, "arr": []}'

Start by reproducing the EmbeddedDocumentListField case with the provided Foo, Bar, and Foo.objects.all().exclude('arr') queryset, then compare it with excluding name and inspect the queryset-to-document loading path. Done means excluding arr prevents the field from appearing in the serialized document, as name exclusion does.