Rank the marks {"Asha": 92, "Ravi": 78, "Meera": 85, "Kabir": 64, "Zoya": 78} from the highest…

The sort key is (-mark, name): the highest mark first, and for equal marks the names in alphabetical order.

1. Asha $92$
2. Meera $85$
3. Ravi $78$
4. Zoya $78$
5. Kabir $64$

Ravi is before Zoya because R comes before Z. Without the second part of the key, a tie would be left in the order in which Python happened to find them.