placebo_session fails without session setup

[boompig]

When using placebo.utils.placebo_session as a decorator, I had the following error:

__________________________________________ test_publish_incidents_placebo __________________________________________

args = (), kwargs = {}, session_kwargs = {'region_name': 'us-east-1'}, profile_name = None
session = Session(region_name='us-east-1')

    @functools.wraps(function)
    def wrapper(*args, **kwargs):
        session_kwargs = {
            'region_name': os.environ.get('AWS_DEFAULT_REGION', 'us-east-1')
        }
        profile_name = os.environ.get('PLACEBO_PROFILE', None)
        if profile_name:
            session_kwargs['profile_name'] = profile_name

        session = boto3.Session(**session_kwargs)

>       self = args[0]
E       IndexError: tuple index out of range

env/lib/python2.7/site-packages/placebo/utils.py:29: IndexError
======================================== 1 failed, 5 passed in 1.92 seconds ========================================
make: *** [test] Error 1