Please who knows how this code works?

Question

Python dictionaries
https://code.sololearn.com/c7Zp6ia1i0Z2/?ref=app

Answer 1

First this code select value with key=3 (value=5).
On the second you try to select value with nonexistent key=5 and get an error

Answer 2

Thank you

Answer 3

Igor Kostrikin How did I select a value with non existent key 5