@sergiusens hello. Do you plan to update https://snapcraft.io/black? It is failing right now https://travis-ci.org/apriha/lineage/jobs/523805283#L284
$ black --check --diff . Traceback (most recent call last): File "/snap/black/1/bin/black", line 11, in <module> load_entry_point('black==18.6b4', 'console_scripts', 'black')() File "/snap/black/1/lib/python3.6/site-packages/click/core.py", line 722, in __call__ return self.main(*args, **kwargs) File "/snap/black/1/lib/python3.6/site-packages/click/core.py", line 676, in main _verify_python3_env() File "/snap/black/1/lib/python3.6/site-packages/click/_unicodefun.py", line 118, in _verify_python3_env 'for mitigation steps.' + extra) RuntimeError: Click will abort further execution because Python 3 was configured to use ASCII as encoding for the environment. Consult http://click.pocoo.org/python3/for mitigation steps. This system supports the C.UTF-8 locale which is recommended. You might be able to resolve your issue by exporting the following environment variables: export LC_ALL=C.UTF-8 export LANG=C.UTF-8 Click discovered that you exported a UTF-8 locale but the locale system could not pick up from it because it does not exist. The exported locale is "en_US.UTF-8" but it is not supported The command "black --check --diff ." exited with 1.