two flake8 fixes
diff --git a/src/cryptography/hazmat/primitives/serialization.py b/src/cryptography/hazmat/primitives/serialization.py
index 858ec04..0dbbc85 100644
--- a/src/cryptography/hazmat/primitives/serialization.py
+++ b/src/cryptography/hazmat/primitives/serialization.py
@@ -6,7 +6,6 @@
 
 import base64
 import struct
-import sys
 import warnings
 
 from cryptography import utils
@@ -99,7 +98,6 @@
     return _int_from_bytes(mpint_data, byteorder='big', signed=False), rest
 
 
-
 if hasattr(int, "from_bytes"):
     _int_from_bytes = int.from_bytes
 else: