diff --git a/third_party/2and3/cryptography/hazmat/primitives/serialization/__init__.pyi b/third_party/2and3/cryptography/hazmat/primitives/serialization/__init__.pyi
index 103048784..4a8062167 100644
--- a/third_party/2and3/cryptography/hazmat/primitives/serialization/__init__.pyi
+++ b/third_party/2and3/cryptography/hazmat/primitives/serialization/__init__.pyi
@@ -2,10 +2,12 @@ from abc import ABCMeta
 from enum import Enum
 from typing import Optional
 
-def load_pem_private_key(data: bytes, password: Optional[bytes], backend): ...
-def load_pem_public_key(data: bytes, backend): ...
-def load_der_private_key(data: bytes, password: Optional[bytes], backend): ...
-def load_der_public_key(data: bytes, backend): ...
+from cryptography.hazmat.backends.interfaces import DERSerializationBackend, PEMSerializationBackend
+
+def load_pem_private_key(data: bytes, password: Optional[bytes], backend: Optional[PEMSerializationBackend] = ...): ...
+def load_pem_public_key(data: bytes, backend: Optional[PEMSerializationBackend] = ...): ...
+def load_der_private_key(data: bytes, password: Optional[bytes], backend: Optional[DERSerializationBackend] = ...): ...
+def load_der_public_key(data: bytes, backend: Optional[DERSerializationBackend] = ...): ...
 def load_ssh_public_key(data: bytes, backend): ...
 
 class Encoding(Enum):