json encoding and decoding does not always work together

[gkhaburzaniya]

Python 3.4, botoflow 0.8, django 1.9

When the cause of an ActivityTaskFailed is that a django model's .get() raised DoesNotExist, or MultipleObjectsReturned (and probably for many other errors). The JSON encoder encodes this into the details here

https://github.com/boto/botoflow/blob/master/botoflow/data_converter/json_data_converter.py#L152

That leads to something like this "__obj": [ "app.models:DoesNotExist", {}]

Which causes an error when trying to decode it here https://github.com/boto/botoflow/blob/master/botoflow/data_converter/json_data_converter.py#L189, since app.models does not have DoesNotExist, the DoesNotExist is part of the model class which raised the error. IMO, the encoding should write something like

        "__obj": [
            "app.models:ModelName.DoesNotExist",
            {}]

instead. That might be impossible though :(