input: from typing import List
  
  def extract_urls(webpage_url: str) -> List[str]:
      """ Extracts URLs from a given webpage using BeautifulSoup.
      >>> extract_urls("https://example.com")
      ['http://example.com/page1', 'http://example.com/page2', 'http://example.com/page3']
      """
      import requests
      from bs4 import BeautifulSoup
  
      # Get the web page
      webpage = requests.get(webpage_url)
  
      # Parse the web page
      soup = BeautifulSoup(webpage.content, 'html.parser')
  
      # Find all 'a' tags
      links = soup.find_all('a')
  
      # Extract the URLs in the 'href' attribute
      urls = [link.get('href') for link in links]
      return urls
output:     # Filter out None values and ensure URLs are absolute
      from urllib.parse import urljoin
      base_url = webpage_url
      urls = [urljoin(base_url, url) for url in urls if url and url.startswith('http')]
      return urls