ImportError: cannot import name 'collection'

[mikostn]

Hi,
I've run in to an error, just after installing requirements and making initial setup ;)

I followed: http://jeffersonheard.github.io/sondra/basics/tutorial-1/

Traceback (most recent call last):
  File "flapi.py", line 4, in <module>
    from sondra.collection import Collection
  File "/usr/local/lib/python3.4/dist-packages/sondra/collection/__init__.py", line 11, in <module>
    from sondra.api.expose import method_schema, expose_method_explicit
  File "/usr/local/lib/python3.4/dist-packages/sondra/api/__init__.py", line 1, in <module>
    from .api_request import *
  File "/usr/local/lib/python3.4/dist-packages/sondra/api/api_request.py", line 12, in <module>
    from sondra import formatters
  File "/usr/local/lib/python3.4/dist-packages/sondra/formatters/__init__.py", line 3, in <module>
    from .geojson import GeoJSON
  File "/usr/local/lib/python3.4/dist-packages/sondra/formatters/geojson.py", line 4, in <module>
    from sondra import collection
ImportError: cannot import name 'collection'

I'm looking for a solution to build secure RESTfull API for my RethikDB project, Sondra looks like exactly what I need.
I'd be very thankful for some support.