python - Pull from a list in a dict using mongoengine -

i have document in mongo engine:

class mydoc(db.document):     x = db.dictfield()     item_number = intfield() 

and have data document

{     "_id" : objectid("55e360cce725070909af4953"),     "x" : {         "mongo" : [             {                 "list" : "lista"             },             {                 "list" : "listb"             }         ],         "hello" : "world"     },     "item_number" : 1 } 

ok if want push mongo list using mongoengine, this:

mydoc.objects(item_number=1).update_one(push__x__mongo={"list" : "listc"}) 

that works pretty well, if query database again this

{     "_id" : objectid("55e360cce725070909af4953"),     "x" : {         "mongo" : [             {                 "list" : "lista"             },             {                 "list" : "listb"             },             {                 "list" : "listc"             }         ],         "hello" : "world"     },     "item_number" : 1 } 

but when try pull same list using pull in mongo engine:

mydoc.objects(item_number=1).update_one(pull__x__mongo={'list': 'lista'}) 

i error:

mongoengine.errors.operationerror: update failed (cannot apply $pull non-array value)

comparising sentences:

mydoc.objects(item_number=1).update_one(push__x__mongo={"list" : "listc"}) # works mydoc.objects(item_number=1).update_one(pull__x__mongo={"list" : "listc"}) # error 

how can pull list?

i appreciate help

i believe problem mongoengine doesn't know structure of x document. declared dictfield, mongoengine thinks pulling dictfield not listfield. declare x listfield , both queries should work fine.

i suggest should create issue this:
https://github.com/mongoengine/mongoengine/issues

as workaround, can use raw query:

mydoc.objects(item_number=1).update_one(__raw__={'$pull': {'x.mongo': {'list': 'listc'}}})