input: Write a python function to extract all URLs from a paginated website using requests and BeautifulSoup.
  assert extract_urls('https://example.com') == ['https://example.com/page1', 'https://example.com/page2', 'https://example.com/page3']
  assert extract_urls('https://example.com/blog') == ['https://example.com/blog/page1', 'https://example.com/blog/page2']
  assert extract_urls('https://example.com/articles') == ['https://example.com/articles/page1', 'https://example.com/articles/page2', 'https://example.com/articles/page3', 'https://example.com/articles/page4']
output: def extract_urls(base_url):
      import requests
      from bs4 import BeautifulSoup
      urls = []
      page_number = 1
      while True:
          url = f"{base_url}/page{page_number}"
          response = requests.get(url)
          if response.status_code != 200:
              break
          soup = BeautifulSoup(response.content, 'html.parser')
          if not soup.find():  # Assuming if the page is empty, pagination ends
              break
          urls.append(url)
          page_number += 1
      return urls