From 5fe546c70c49778bcfa84f684faef7d3aa9b0c32 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sun, 20 Feb 2011 12:10:01 -0700
Subject: [PATCH] ...

---
 src/calibre/ebooks/metadata/xisbn.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/calibre/ebooks/metadata/xisbn.py b/src/calibre/ebooks/metadata/xisbn.py
index 2ee74396c7..aaeb1c6b98 100644
--- a/src/calibre/ebooks/metadata/xisbn.py
+++ b/src/calibre/ebooks/metadata/xisbn.py
@@ -11,6 +11,12 @@ from calibre import browser
 
 class xISBN(object):
 
+    '''
+    This class is used to find the ISBN numbers of "related" editions of a
+    book, given its ISBN. Useful when querying services for metadata by ISBN,
+    in case they do not have the ISBN for the particular edition.
+    '''
+
     QUERY = 'http://xisbn.worldcat.org/webservices/xid/isbn/%s?method=getEditions&format=json&fl=form,year,lang,ed'
 
     def __init__(self):