pre-commit: Unknown Encoding error

I get the following error on commit

An unexpected error has occurred: LookupError: unknown encoding:
Traceback (most recent call last):
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/error_handler.py", line 47, in error_handler
    yield
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/main.py", line 195, in main
    return run(runner, args)
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/commands/run.py", line 210, in run
    repo_hooks = list(get_repo_hooks(runner))
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/commands/run.py", line 159, in get_repo_hooks
    for repo in runner.repositories:
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/cached_property.py", line 26, in __get__
    value = obj.__dict__[self.func.__name__] = self.func(obj)
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/runner.py", line 46, in repositories
    repository.require_installed()
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/repository.py", line 174, in require_installed
    _install_all(self._venvs, self.repo_config['repo'])
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/repository.py", line 68, in _install_all
    for cmd_runner, language_name, version, deps in venvs
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/repository.py", line 69, in <genexpr>
    if not _installed(cmd_runner, language_name, version, deps)
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/repository.py", line 60, in _installed
    _read_installed_state(cmd_runner, venv) == _state(additional_deps)
  File "/usr/local/Cellar/pre-commit/0.13.2/libexec/lib/python2.7/site-packages/pre_commit/repository.py", line 43, in _read_installed_state
    return json.loads(io.open(filename).read())
LookupError: unknown encoding: