Hello to all, i just wonder why i am getting an error for my converted string into datetime.

I have these fields:

current_year  = form['year_id'][1]

date_range = datetime.strptime(str(current_year)+'-01-01','%Y-%m-%d').date()

total_month_elapsed = (book_list.date_from.year - date_range.year) * 12 + book_list.date_from.month - date_range.month

I don't know when date_range is read the terminal says:

    date_range = datetime.strptime(str(current_year)+'-01-01','%Y-%m-%d').date()
TypeError: must be string, not datetime.date

Any help is much appreciated.