Improve `six` usage (`xrange`, `map,` zip`)#2264

Merged

menshikh-iv merged 3 commits intopiskvorky:developfrom horpto:izip-xrange

Dec 17, 2018

+137-138

Commits on Dec 12, 2018

replace xrange with range + import from six.moves
horpto
committed

Commits on Dec 16, 2018