code: def get_hostname(url):
          
  
          if url not in URLHelper.__cache:
              URLHelper.__cache[url] = urlparse(url)
  
          parts = URLHelper.__cache[url].netloc.split(".")
  
          if len(parts) == 1:
              return parts[0]
          else:
              return ".".join(parts[-2:-1])
docs: Get the hostname of the given URL.
  
          Args:
              url (str): The URL to get the hostname from.
  
          Returns:
              str: The hostname