Arc doesn't work

I can't use arc. At the end of 'arc diff' it says Exception Some linters failed: - CommandException: Command failed with error #1! COMMAND python3 .arc-linters/check-cpp.py 'compiler/basicTypes/Id.hs' STDOUT (empty) STDERR File ".arc-linters/check-cpp.py", line 28 r = re.compile(rb'ASSERT\s+\(') ^ SyntaxError: invalid syntax (Run with `--trace` for a full exception trace.) simonpj@cam-05-unx:~/code/HEAD-3$ python3 --version python3 --version Python 3.2.3 Alas. Simon