input: from typing import List, Set
  from bs4 import BeautifulSoup
  import requests
  import re
  
  def crawl(url: str) -> Set[str]:
      """Creates a web crawler that starts from a given URL, searches for other links on the page, and scrapes the page content. The crawler uses a Breadth-First Search (BFS) approach to traverse the links and collects all visited links.
  
      >>> crawl('https://example.com')
      {'https://example.com', 'https://example.com/about', 'https://example.com/contact'}
      """
      visited = set()
      queue = [url]
      
      while queue:
          curr = queue.pop(0)
          visited.add(curr)
          response = requests.get(curr)
          
          if response.ok:
              soup = BeautifulSoup(response.text, 'html.parser')
              
              # Scrape the page here
              
              # Find all the links
              links = soup.find_all('a', href=re.compile('^http'))
              
              for link in links:
                  if link['href'] not in visited:
                      queue.append(link['href'])
      return visited
output:     visited = set()
      queue = [url]
      
      while queue:
          curr = queue.pop(0)
          visited.add(curr)
          response = requests.get(curr)
          
          if response.ok:
              soup = BeautifulSoup(response.text, 'html.parser')
              
              # Scrape the page here
              
              # Find all the links
              links = soup.find_all('a', href=re.compile('^http'))
              
              for link in links:
                  if link['href'] not in visited:
                      queue.append(link['href'])
      return visited