SQL output to a dictionary of list

I am trying to convert the following o/p of my SQL query (as a dataframe) to a dictionary of list:

Column A   Column B
M             N
M             O

I want the result in following format:

{M:[N,O]}

Can someone help me in this?

>Solution :

You could try like this:

a_dict = df.groupby('Column A', as_index=True)['Column B'].apply(list).to_dict()

print(a_dict)
{'M': ['N', 'O']}