This Python module provides a xopen function that works like the built-
in open function, but can also deal with compressed files. Supported
compression formats are gzip, bzip2 and xz. They are automatically
recognized by their file extensions .gz, .bz2 or .xz.

The focus is on being as efficient as possible on all supported Python
versions. For example, simply using gzip.open is slow in older Pythons,
and it is a lot faster to use a gzip subprocess.

This module has originally been developed as part of the cutadapt tool
that is used in bioinformatics to manipulate sequencing data. It has
been in successful use within that software for a few years.