input: Write a python function to parse a URL and extract its protocol, domain name, and path.
  assert parse_url('https://www.example.com/path/to/file') == ('https', 'www.example.com', '/path/to/file')
  assert parse_url('http://www.testsite.com/test/path') == ('http', 'www.testsite.com', '/test/path')
  assert parse_url('ftp://fileserver.com/files') == ('ftp', 'fileserver.com', '/files')
output: def parse_url(url):
      from urllib.parse import urlparse
      parsed_url = urlparse(url)
      protocol = parsed_url.scheme
      domain = parsed_url.netloc
      path = parsed_url.path
      return (protocol, domain, path)