code: def _get_private_key(cls, private_key_path, private_key_passphrase):
          
          if private_key_path is None or private_key_passphrase is None:
              return None
  
          with open(private_key_path, 'rb') as key:
              p_key = serialization.load_pem_private_key(
                  key.read(),
                  password=private_key_passphrase.encode(),
                  backend=default_backend())
  
          return p_key.private_bytes(
              encoding=serialization.Encoding.DER,
              format=serialization.PrivateFormat.PKCS8,
              encryption_algorithm=serialization.NoEncryption())
docs: Get Snowflake private key by path or None.