How to find the last value of a dictionary key by value?

Question

Python

Hello! I'm trying to solve this problem
here is my code, which I started solving this problem
https://colab.research.google.com/drive/1wIAiJt1GX...
i.e. for each dictionary value, select the last value of the dictionary key. When I try to iterate over a dictionary, and its keys are duplicated, only unique values ​​come out. Please tell me in which direction I should dig to solve the problem