input: Write a function to generate Python code for crawling a website to extract a specific type of data. The function should take in a website URL and the data to crawl, and return the extracted data in the form of a list or other suitable data structure. Use the requests library to fetch the website content and the re library to parse the content for the desired data. 
  
  assert crawl_website_for_data('www.example.com', 'phone numbers')==['123-456-7890', '987-654-3210']
  assert crawl_website_for_data('www.example.com', 'email addresses')==['test@example.com', 'support@example.com']
  assert crawl_website_for_data('www.example.com', 'job titles')==['Software Engineer', 'Data Analyst']
  assert crawl_website_for_data('www.example.com', '')==[]
  assert crawl_website_for_data('', 'phone numbers')==[]
output: def crawl_website_for_data(url, data_type):
      if not url:
          return []
      import requests
      import re
      response = requests.get(f'http://{url}')
      content = response.text
      if data_type == 'phone numbers':
          pattern = r'\b\d{3}-\d{3}-\d{4}\b'
      elif data_type == 'email addresses':
          pattern = r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b'
      elif data_type == 'job titles':
          pattern = r'\b(?:Software Engineer|Data Analyst)\b'
      else:
          return []
      return re.findall(pattern, content)