Use random.getrandbits for compatibility with python 3.8

test/conftest.py

@@ -11,7 +11,7 @@ def stabilize_random():
     set_random_seed(42)
 
     def urandom_mock(n):
-        return random.randbytes(n)
+        return bytes(random.getrandbits(8) for _ in range(n))
 
     # os.random is the source of random used in the uuid library
     # normally, it's „true“ random, but to stabilize tests,