Uses chain instead of chain.from_iterable.
Uses chain instead of chain.from_iterable.

OrkoHunter/networkx,Sixshaman/networkx,goulu/networkx,michaelpacer/networkx,JamesClough/networkx,NvanAdrichem/networkx,andnovar/networkx,jfinkels/networkx,SanketDG/networkx,cmtm/networkx