diff --git a/pep-3123.txt b/pep-3123.txt
index 815f3b022..5108d9676 100644
--- a/pep-3123.txt
+++ b/pep-3123.txt
@@ -45,8 +45,8 @@ code has undefined behavior::
 The problem here is that the storage is both accessed as
 if it where struct PyObject, and as struct FooObject.
 
-Historically, compilers did not cause any problems with this
-code. However, modern compiler use that clause as an 
+Historically, compilers did not have any problems with this
+code. However, modern compilers use that clause as an 
 optimization opportunity, finding that f->ob_refcnt and
 o->ob_refcnt cannot possibly refer to the same memory, and
 that therefore the function should return 0, without having
@@ -110,7 +110,18 @@ ob_type, a macro::
 
   #define Py_Type(o) (((PyObject*)o)->ob_type)
 
-is added.
+is added. E.g. the code blocks::
+
+  #define PyList_CheckExact(op) ((op)->ob_type == &PyList_Type)
+
+  return func->ob_type->tp_name;
+
+needs to be changed to::
+
+  #define PyList_CheckExact(op) (Py_Type(op) == &PyList_Type)
+
+  return Py_Type(func)->tp_name;
+  
 
 Compatibility with Python 2.6
 =============================