Required task
I have the following DataFrame and I want to get the data to simply have the unique count changes of the Rating for each id
             date  Rating  id
0      2019-12-31    A      1
1      2019-12-31    B      2
2      2019-11-30    A      1
3      2019-11-30    A      2
4      2019-10-31    B      1
5      2019-10-31    A      2
6      2019-09-30    C      1
7      2019-09-30    A      2
8      2019-08-31    B      1
9      2019-08-31    B      2
Goal
id   Rating   Unique Count
1      A        1
1      B        2
1      C        1
2      A        1
2      B        2
The above DataFrame is simply an example, I am not exactly sure how it would look it pandas. Any help would be awesome!
