From 323c40d48c4c1661a18336af16c59bc279fda571 Mon Sep 17 00:00:00 2001
From: Benjamin Peterson <benjamin@python.org>
Date: Tue, 6 May 2008 22:31:52 +0000
Subject: [PATCH] Make the Python implementation of warnings compatible with
 the C implementation regarding non-callable showwarning

---
 Lib/warnings.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Lib/warnings.py b/Lib/warnings.py
index d9e6e445872..132a34da287 100644
--- a/Lib/warnings.py
+++ b/Lib/warnings.py
@@ -278,6 +278,9 @@ def warn_explicit(message, category, filename, lineno,
                 _show_warning(message, category, filename, lineno)
             else:
                 warn(showwarning_msg, DeprecationWarning)
+    if not callable(showwarning):
+        raise TypeError("warnings.showwarning() must be set to a "
+                        "function or method")
     # Print message and context
     showwarning(message, category, filename, lineno)