given empty data twice.  Patch by Benjamin Fogle.

Original patch by John Leitch.

Most fixes to Doc/ and Lib/ directories by Ville Skyttä.

GzipFile, BZ2File or LZMAFile.  This defeats denial of service attacks
using compressed bombs (i.e. compressed payloads which decompress to a huge
size).

Patch by Martin Panter and Nikolaus Rath.

Patch by Nikolaus Rath and Martin Panter.

The underlying C libraries provide no mechanism for serializing compressor and
decompressor objects, so actually pickling these classes is impractical.
Previously, these objects would be pickled without error, but attempting to use
a deserialized instance would segfault the interpreter.

Patch by Tim Heaney and Vajrasky Kok.

These functions were originally added to support LZMA compression in the zipfile
module, and are not of interest for the majority of users.

They can be made public in 3.4 if there is user interest, but in the meanwhile,
I've opted to present a smaller, simpler API for the module's initial release.