Can't find mistake in code to scrap data from book store

Below is my code I am using to scrape data from Bookstore but it not working. Error like 404 response none and NotImplementationError callback is generating.

import scrapy

class Book_Store(scrapy.Spider):

name='BookSpider'

def start_requests(self):

    urls=["http://books.toscrape.com/catalogue/page-1.html",]

    for url in urls:

        yield scrapy.Request(url=url, callback=self.parse)

def parse(self, response):

for i in response.css('article.product_pod'):

    image=i.css('div.image_container a img::attr(src)').get()

    booktitle= i.css('h3 a::attr(title)').get()

    bookprice= i.css('div.product_price p.price_color::text').get()

    yield {

        'image_url': image,

        'book_title': booktitle,

        'product_price': bookprice,

    }

           

next_page= response.css('ul.pager li.next a::attr(href)').get()

if next_page is not None:

    next_page= response.urljoin(next_page)

    yield scrapy.Request(next_page, callback=self.parse)