Pep8-ify build_sample_set.py
Pep8-ify build_sample_set.py

bgyori/indra,sorgerlab/belpy,sorgerlab/indra,pvtodorov/indra,johnbachman/indra,johnbachman/indra,pvtodorov/indra,bgyori/indra,johnbachman/belpy,pvtodorov/indra,johnbachman/belpy,bgyori/indra,sorgerlab/indra,sorgerlab/belpy,pvtodorov/indra,johnbachman/indra,johnbachman/belpy,sorgerlab/belpy,sorgerlab/indra