input: def crawl(url: str) -> None:
      """
      Create a web crawler that starts from a given URL and explores other links on the 
      page, scraping the content of each page visited. The crawler uses a breadth-first 
      search approach to visit all reachable links from the initial URL.
      
      >>> crawl('http://example.com')
      # Output: None (output is implementation specific, no explicit return)
      """
output:     import requests
      from bs4 import BeautifulSoup
      from urllib.parse import urljoin
      from collections import deque
  
      visited = set()
      queue = deque([url])
  
      while queue:
          current_url = queue.popleft()
          if current_url in visited:
              continue
  
          try:
              response = requests.get(current_url)
              response.raise_for_status()
          except requests.RequestException:
              continue
  
          visited.add(current_url)
          soup = BeautifulSoup(response.text, 'html.parser')
          print(f"Scraping content from {current_url}")
          # Here you can add code to scrape the content of the page
  
          for link in soup.find_all('a', href=True):
              absolute_url = urljoin(current_url, link['href'])
              if absolute_url not in visited:
                  queue.append(absolute_url)