How can I count the occurrences of unique values within a list in Python?

I have a list of values, and I want to determine the frequency of each unique value in the list. I have attempted to write some code, but I am encountering difficulties and would appreciate some guidance.

Here is an example of my current approach:

However, I am not getting the desired output. Can someone please help me identify the issue and provide a better solution for counting the occurrences of unique values in a list?

Thank you in advance for your assistance!