code: def generate_host_keys(hostname: str) -> Iterator[str]:
      
      labels = hostname.split('.')
      for i in range(2, len(labels) + 1):
          domain = '.'.join(labels[-i:])
          yield domain
          yield '.' + domain
docs: Yield Chrome/Chromium keys for `hostname`, from least to most specific.
  
      Given a hostname like foo.example.com, this yields the key sequence:
  
      example.com
      .example.com
      foo.example.com
      .foo.example.com