make the __in=non_iterable_or_doc tests more concise
make the __in=non_iterable_or_doc tests more concise

cogniteev/mongoengine,MakerReduxCorp/mongoengine,Davidrjx/mongoengine,ConsumerPhysics/mongoengine,MakerReduxCorp/mongoengine,Davidrjx/mongoengine,cogniteev/mongoengine,MongoEngine/mongoengine