To the best of my ability, I believe this to be the same return value as the original code. The original code would have gotten a defaultly constructed ```IndexRange``` (which is ```std::pair<unsigned int, unsigned int>```). That default would have been (0,0). The code then takes those values and adds them to ```container_.begin()``` to get the return values. [NOTE: in the original code the ```.second``` value is compared against 0 and if it is equal the 0 is added to ```container_.begin()```.]