Q$10$:

Create a function called theme$\_$by$\_$year that takes as input a year $($as an integer$)$ and shows the theme ids and theme names $($listed in order by theme id$)$ that were in sets that year.

The column names must be id and name$\_$themes $($to differentiate between the name of a theme and the name of a set$)$ in that order.

The index should be reset and go from $0$ to n$-1.$

Each theme should only be listed once even if it appeared in more than one set from that year $--$ duplicate themes should be based on theme id and not name since there are some themes with the same name but with a different id$.$

Hint: It will help if you were to think about merging appropriate DataFrames to help you get this answer.