input: def read_url(url: str) -> str:
      """ Reads the content from a given URL and returns the text content if the 
      request is successful (status code 200). Returns None otherwise.
      >>> read_url('https://example.com')
      '<!doctype html>...'
      >>> read_url('https://nonexistenturl.com')
      None
      """
      r = requests.get(url)
      if r.status_code == 200:
          return r.text
      else:
          return None
output:     import requests