input: Write a function to parse a given URL and print out the protocol, domain name, and path using Python. The function should use the `urllib.parse.urlparse` method to extract these components from the URL. If the input URL is valid, the function should print the protocol, domain name, and path. If the input URL is invalid, the function should print an error message.
  assert parse_url('https://www.example.com/path/to/file')==None
  # Output: 
  # Protocol: https
  # Domain name: www.example.com
  # Path: /path/to/file
  
  assert parse_url('http://invalid.url')==None
  # Output: 
  # Error: Invalid URL
output: def parse_url(url):
      try:
          parsed_url = urllib.parse.urlparse(url)
          print(f"Protocol: {parsed_url.scheme}")
          print(f"Domain name: {parsed_url.netloc}")
          print(f"Path: {parsed_url.path}")
      except ValueError:
          print("Error: Invalid URL")