"
{
    "_id" : ObjectId("5d019fbdace49e498de7d915"),
    "created_date" : ISODate("2018-05-18T16:00:00.000Z"),
    "published_date" : ISODate("2018-05-18T16:00:00.000Z")
}
"

'created_date':{'$date': 1463587200000}

mongoengine.errors.ValidationError: ValidationError (MyObject:5d019aca1c9d4400008cb934) (cannot parse date "{'$date': 1463587200000}"