To second the sibling comment, "UTC" doesn't appear in the article at all. "timezone" occurs in code samples only. "timestamp" appears exactly once in this sentence:

> Let’s say we define a python function `convert_to_eastern` that takes a timestamp and converts it to the eastern time zone.

It seems unlikely this 2-week old article was updated within the last 2 hours so I'm not sure which article you're quoting.