I have an issue in my code when trying to input a published date for a new book entry

def clean_date(date_str):        
    months = ['January', 'February', 'March', 'April', 'May', 'June', 
              'July', 'August', 'September', 'October', 'November', 'December']
    split_date = date_str.split('  ')
    try:
        month = int(months.index(split_date[0]) + 1)
        day = int(split_date[1].split(',')[0])
        year = int(split_date[2])
        return_date = datetime.date(year, month, day)
    except ValueError:
        input('''
          \n****** DATE ERROR ******
          \rThe date format should include a valid Month day, year from the past.
          \rEx: January 13, 2003
          \rPress enter to try again.
          \r************************''')
        return
    else:
        return return_date


    def app():
    app_running = True
    while app_running:
        choice = menu()
        if choice == '1':
            title = input('Title: ')
            author = input('Author: ')
            date_error = True
            while date_error:
                date = input('Published Date (Ex: October 25, 2017): ')
                date = clean_date(date)
                if type(date) == datetime.date:
                    date_error = False
            price_error = True
            while price_error:        
                price = input('Price (Ex: 25.64): ')
                price = clean_price(price)
                if type(price) == int:
                    price_error = False
            new_book = Book(title = title, author = author,
                            published_date = date, price = price)
            session.add(new_book)
            session.commit()
            print('Book Added!')
            time.sleep(1.5)
        elif choice == '2': 
            for book in session.query(Book):
                print(f'{book.id} | {book.title} | {book.author}')
            input('\nPress enter to return to the main menu.')    
        elif choice == '3':
            id_options = []
            for book in session.query(Book):
                id_options.append(book.id)
            id_error = True
            while id_error:    
                id_choice = input(f'''
                \nId options:  {id_options}
                \rBook ID: ''')   
                id_choice = clean_id(id_choice, id_options)
                if type(id_choice) == int:    
                    id_error = False 
            the_book = session.query(Book).filter(Book.id == id_choice).first()
            print(f'''
              \n{the_book.title} by {the_book.author}
              \rPublished: {the_book.published_date}
              \rPrice:  ${the_book.price / 100}
              ''')
            sub_choice = submenu()
            if sub_choice == '1':

                pass
            elif sub_choice == '2':

                pass
        elif choice == '4':

            pass
        else:
            print('GOODBYE')
            app_running = False