diff --git a/OpenSSL/crypto.py b/OpenSSL/crypto.py
index 3b8abeb..d642c6c 100644
--- a/OpenSSL/crypto.py
+++ b/OpenSSL/crypto.py
@@ -1487,7 +1487,7 @@
         :param X509 cert: The certificate to add to this store.
         :raises TypeError: If the certificate is not an :py:class:`X509`.
         :raises Error: If OpenSSL was unhappy with your certificate.
-        :return: py:data:`None` if the certificate was added successfully.
+        :return: :py:data:`None` if the certificate was added successfully.
         """
         if not isinstance(cert, X509):
             raise TypeError()