Have CertificateBuilder docs create self-signed cert
diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index 0fea616..b2192c4 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -546,11 +546,7 @@
... key_size=2048,
... backend=default_backend()
... )
- >>> public_key = rsa.generate_private_key(
- ... public_exponent=65537,
- ... key_size=2048,
- ... backend=default_backend()
- ... ).public_key()
+ >>> public_key = private_key.public_key()
>>> builder = x509.CertificateBuilder()
>>> builder = builder.subject_name(x509.Name([
... x509.NameAttribute(NameOID.COMMON_NAME, u'cryptography.io'),