Merged revisions 86092 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

........
  r86092 | steven.bethard | 2010-11-01 17:29:26 +0100 (Mon, 01 Nov 2010) | 1 line

  Fix for issue 9355 where with multiple mutually exclusive arguments, some brackets were being lost in the usage messages
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diff --git a/Lib/argparse.py b/Lib/argparse.py
index 9597a67..318e49b 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -392,10 +392,16 @@
                     for action in group._group_actions:
                         group_actions.add(action)
                     if not group.required:
-                        inserts[start] = '['
+                        if start in inserts:
+                            inserts[start] += ' ['
+                        else:
+                            inserts[start] = '['
                         inserts[end] = ']'
                     else:
-                        inserts[start] = '('
+                        if start in inserts:
+                            inserts[start] += ' ('
+                        else:
+                            inserts[start] = '('
                         inserts[end] = ')'
                     for i in range(start + 1, end):
                         inserts[i] = '|'