How to return the column title wherein the row contains the greatest value in Pandas Dataframe [duplicate]

Question

I working on a Python project that has a DataFrame like this:

data = {'AAA':  [3, 8, 2, 1],
        'BBB':  [5, 4, 7, 2],
        'CCC':  [2, 5, 6, 4]}
df = pd.DataFrame(data)

which leads to:

	AAA	BBB	CCC
0	3	5	2
1	8	4	5
2	2	7	6
3	1	2	4

And the task consists of generating the following DataFrame:

	AAA	BBB	CCC	Role
0	3	5	2	BBB
1	8	4	5	AAA
2	2	7	6	BBB
3	1	2	4	CCC

Where "Role" column elements are the column headers that have the highest value in the row in which it is located.

Could you please help me by suggesting a code that solves this task?