In we dealt with a few call sites for map that weren't converted to account for the Python 3 implementation. We should:
make sure that other functions that started returning iterators in Python 3 are used correctly (i.e. that they are consumed somewhere if they're expected to actually iterate, and they're only used once)
convert uses of these functions to use the six.moves implementations. This will make these functions perform consistently between Pythons 2 and 3, rather than calculating on iteration on Py3 and calculating in a batch on Py2.