reorder CertificateBuilder sign arguments
diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index 799126b..61971fe 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -502,15 +502,10 @@
         :param critical: Set to ``True`` if the extension must be understood and
              handled by whoever reads the certificate.
 
-    .. method:: sign(backend, private_key, algorithm)
+    .. method:: sign(private_key, algorithm, backend)
 
         Sign the certificate using the CA's private key.
 
-        :param backend: Backend that will be used to build the certificate.
-            Must support the
-            :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
-            interface.
-
         :param private_key: The
             :class:`~cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey`,
             :class:`~cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey` or
@@ -521,6 +516,11 @@
             :class:`~cryptography.hazmat.primitives.hashes.HashAlgorithm` that
             will be used to generate the signature.
 
+        :param backend: Backend that will be used to build the certificate.
+            Must support the
+            :class:`~cryptography.hazmat.backends.interfaces.X509Backend`
+            interface.
+
 
 X.509 CSR (Certificate Signing Request) Object
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~