AttributeError: 'AWSResponse' object has no attribute 'raw_headers'

[ampx-mg]

This is caused by aio-libs/aiobotocore#755, in short some code using aioboto cannot be properly mocked with moto as there is no aiomoto.

A (integration) test catching this error should be introduced, otherwise there is no way of knowing if the dependencies set by this repo are 100% functional, that's why #6 tests passed without issues.