> Additionally, if the hash contains duplicate keys, swapping the keys and values may not have the desired effect.
You can't have duplicate keys in a hash.
More importantly, their implementation adds the swapped pairs but does not remove the original k/v pairs, which is both incorrect and does not match the output it prints.
> The 2017 call records tally remained far less than an estimated billions of records collected per day under the NSA’s old bulk surveillance system, which was exposed by former U.S. intelligence contractor Edward Snowden in 2013.
If you found this interesting, you might also like this classic Neal Stephenson piece for Wired, "Mother Earth, Motherboard": https://www.wired.com/1996/12/ffglass/
> After turning a slight profit in the in the first quarter of this year, Uber lost $100 million in the U.S. in the second quarter. The loss increased in the third quarter, the person said.
That's not exactly a ringing endorsement of their U.S. business.