Check if multiple columns exist in a df

Question

I am wondering how to properly check if multiple columns exist in a df, say if I want to test if both columns A and B exist in df:

if `A` in df and `B` in df:
    # some code

is there a better way to do this checking? tested with ['A', 'B'] in df, but failed.

UPDATE

 pd.Series(['A', 'B']).isin(df.columns).all()

will do the work.