question $4$:Objective: Compute new variables$/$column

Create a function called compute$\_$profit$\_$per$\_$dollar$\_$sold that receives as an argument a pandas dataframe. It should add a new column named profit$\_$per$\_$dollar$\_$sold which should be computed as the ratio between values in column Profit and values in column Sales. It should return the dataframe with the new column $($do not change the column order and leave the new column at the end of the dataframe$).$

Example of usage:

new$\_$df $=$ compute$\_$profit$\_$per$\_$dollar$\_$sold$($df$),$

df is a pandas dataframe that has the columns "Profit" and "Sales"

new$\_$df as the same information as df plus a column "profit$\_$per$\_$dollar$\_$sold"