The problem here is #800788 (python3-astroid: not fit for Python 3.5), which is upstream.
If there isn't going to be fix in the short term a solution would be to build requirements-detector temporarily against python3 instead of python3-all. DS -- 4096R/DF5182C8 46CB 1CA8 9EA3 B743 7676 1DB9 15E0 9AF4 DF51 82C8 LPI certified Linux admin (LPI000329859 64mz6f7kt4) http://www.danielstender.com/blog/
