diff --git a/pep-0316.txt b/pep-0316.txt
index 65d0aed8553..0c63f661e90 100644
--- a/pep-0316.txt
+++ b/pep-0316.txt
@@ -298,7 +298,7 @@ A somewhat contrived example::
            Returns None if no message is available.
 
            pre: self.is_open() # we must have an open connection
-           post: __return__ == None or isinstance(__return__, Message)
+           post: __return__ is None or isinstance(__return__, Message)
            """
 
     class ComplexMailClient(SimpleMailClient):