>>> credits.columns
Index(['movie_id', 'title', 'cast', 'crew'], dtype='object')

>>> credits.cast.values[0].columns
Index(['cast_id', 'character', 'credit_id', 'gender', 'id', 'name', 'order'], dtype='object')

>>> credits.cast.apply(lambda df: df.gender)
AttributeError: 'DataFrame' object has no attribute 'gender'