code: def generate_wildcard_pem_bytes():
      
      key = generate_private_key(u'rsa')
      name = x509.Name([x509.NameAttribute(NameOID.COMMON_NAME, u'*')])
      cert = (
          x509.CertificateBuilder()
          .issuer_name(name)
          .subject_name(name)
          .not_valid_before(datetime.today() - timedelta(days=1))
          .not_valid_after(datetime.now() + timedelta(days=3650))
          .serial_number(int(uuid.uuid4()))
          .public_key(key.public_key())
          .sign(
              private_key=key,
              algorithm=hashes.SHA256(),
              backend=default_backend())
          )
  
      return b''.join((
          key.private_bytes(
              encoding=serialization.Encoding.PEM,
              format=serialization.PrivateFormat.TraditionalOpenSSL,
              encryption_algorithm=serialization.NoEncryption()),
          cert.public_bytes(serialization.Encoding.PEM)
      ))
docs: Generate a wildcard (subject name '*') self-signed certificate valid for
      10 years.
  
      https://cryptography.io/en/latest/x509/tutorial/#creating-a-self-signed-certificate
  
      :return: Bytes representation of the PEM certificate data