Fix false positive test on _instance
Fix false positive test on _instance

DavidBord/mongoengine,Davidrjx/mongoengine,cogniteev/mongoengine,larsbutler/mongoengine,MakerReduxCorp/mongoengine,MakerReduxCorp/mongoengine,MRigal/mongoengine,RussellLuo/mongoengine,sourcelair/mongoengine,ProgressivePlanning/mongoengine,touilleMan/mongoengine,MongoEngine/mongoengine,cogniteev/mongoengine,Davidrjx/mongoengine,ConsumerPhysics/mongoengine