Noticed in a patch review around LZMModules/_lzmamodule.c:1055 that the C-level LZMADecompressor object is being initialized in an __init__() method. It crashes if you create the object with __new__() and never call __init__():

>>> from lzma import LZMADecompressor
>>> LZMADecompressor.__new__(LZMADecompressor).decompress(bytes())
Segmentation fault (core dumped)
[Exit 139]