Found using Clang's static analyzer.

argument values in debug mode.  Patch by Victor Stinner.

category [No]; only those of category [Nd].  (Backport of r74237
from py3k.)

  Reviewed by Amaury.

This is a verifier for the binary code used by the _sre module (this
is often called bytecode, though to distinguish it from Python bytecode
I put it in quotes).

I wrote this for Google App Engine, and am making the patch available as
open source under the Apache 2 license.  Below are the copyright
statement and license, for completeness.

# Copyright 2008 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

It's not necessary to include these copyrights and bytecode in the
source file.  Google has signed a contributor's agreement with the PSF
already.

 http://mail.python.org/pipermail/python-dev/2008-June/079988.html

Python 2.6 should stick with PyString_* in its codebase.  The PyBytes_* names
in the spirit of 3.0 are available via a #define only.  See the email thread.

SRE_MATCH so that signal handlers can be invoked during
long regular expression matches.  It also adds a new
error return value indicating that an exception
occurred in a signal handler during the match, allowing
exceptions in the signal handler to propagate up to the
main loop.  Thanks Josh Hoyt and Ralf Schmitt.