[Biopython] cannot import name '_aligners', Python 3.6.5

[Sergio Valqui]

Hi All,
I just starting to look at Biopython , I've downloaded it from Github and tried to run the test

~/biopython-master/Tests$ python3 run_tests.py

And is returning a lot of errors as:

    from Bio.Align import _aligners
ImportError: cannot import name '_aligners'

Can someone please point me to where/how I can address this?

Thank you.

Sergio.