* Correctly handle file modes when detecting placeholders
4.1.1
* Correctly handle placeholder strings ('-', '_') as arguments to xopen
4.1.0
* Add support for zstd * Adjusted default compression levels based on benchmarking of compression tools. * Handle placeholder strings ('-', '_') as arguments to xopen
4.0.8
* Add pathlib.PurePath as a member of the PathLike type, to work around the lack of os.PathLike as a static superclass of PurePath in python 3.6
4.0.7
* Don't complain when writing a bgzip file and the extension is gz * Reformat codebase using black, and other code cleanup