input: Write a python function to extract the domain name from a given URL.
  assert get_domain_name("https://www.google.com")== "www.google.com"
  assert get_domain_name("http://example.org/some/path")== "example.org"
  assert get_domain_name("https://subdomain.example.co.uk/page")== "subdomain.example.co.uk"
output: def get_domain_name(url):
      from urllib.parse import urlparse
      parsed_url = urlparse(url)
      return parsed_url.netloc