diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c
index e3729902d88..ef06b43ca6e 100644
--- a/Modules/_io/iobase.c
+++ b/Modules/_io/iobase.c
@@ -42,8 +42,8 @@ PyDoc_STRVAR(iobase_doc,
     "bytes. bytearrays are accepted too, and in some cases (such as\n"
     "readinto) needed. Text I/O classes work with str data.\n"
     "\n"
-    "Note that calling any method (even inquiries) on a closed stream is\n"
-    "undefined. Implementations may raise IOError in this case.\n"
+    "Note that calling any method (except additional calls to close(),\n"
+    "which are ignored) on a closed stream should raise a ValueError.\n"
     "\n"
     "IOBase (and its subclasses) support the iterator protocol, meaning\n"
     "that an IOBase object can be iterated over yielding the lines in a\n"