input: Write a python function to crawl a website for phone numbers in the format xxx-xxx-xxxx.
  assert crawl_website_for_phone_numbers('http://example.com/test1')==['123-456-7890', '987-654-3210']
  assert crawl_website_for_phone_numbers('http://example.com/test2')==['111-222-3333']
  assert crawl_website_for_phone_numbers('http://example.com/test3')==[]
output: import re
  import requests
  from bs4 import BeautifulSoup
  
  def crawl_website_for_phone_numbers(url):
      response = requests.get(url)
      page_content = response.text
  
      phone_numbers = re.findall(r'\b\d{3}-\d{3}-\d{4}\b', page_content)
      return phone_numbers