docs: def load_private_key(pem_path, passphrase_bytes=None):
      """Load private key from PEM encoded file"""
      with open(pem_path, "rb") as f:
          return cryptography.hazmat.primitives.serialization.load_pem_private_key(
              data=f.read(),
              password=passphrase_bytes,
              backend=cryptography.hazmat.backends.default_backend(),
          )