Charm upgrade appends ')' at the end of /usr/local/bin/auto_lint.py

After upgrading charm from stable (rev 1) to candidate (rev 2), juju unit enters "error" state with the following error printed out in the debug-log:

unit-juju-lint-test-0: 13:07:18 ERROR unit.juju-lint-test/0.juju-log auto_lint.py failed with this output:
  File "/usr/local/bin/auto_lint.py", line 281
    )
    ^
SyntaxError: unmatched ')'

unit-juju-lint-test-0: 13:07:18 ERROR unit.juju-lint-test/0.juju-log Uncaught exception while in charm code:
Traceback (most recent call last):
  File "./src/charm.py", line 125, in <module>
    main(JujuLintCharm)
  File "/var/lib/juju/agents/unit-juju-lint-test-0/charm/venv/ops/main.py", line 431, in main
    _emit_charm_event(charm, dispatcher.event_name)
  File "/var/lib/juju/agents/unit-juju-lint-test-0/charm/venv/ops/main.py", line 142, in _emit_charm_event
    event_to_emit.emit(*args, **kwargs)
  File "/var/lib/juju/agents/unit-juju-lint-test-0/charm/venv/ops/framework.py", line 283, in emit
    framework._emit(event)
  File "/var/lib/juju/agents/unit-juju-lint-test-0/charm/venv/ops/framework.py", line 743, in _emit
    self._reemit(event_path)
  File "/var/lib/juju/agents/unit-juju-lint-test-0/charm/venv/ops/framework.py", line 790, in _reemit
    custom_handler(event)
  File "./src/charm.py", line 91, in on_config_changed
    self.helper.run_auto_lint()
  File "/var/lib/juju/agents/unit-juju-lint-test-0/charm/lib/lib_jujulint.py", line 183, in run_auto_lint
    raise error
  File "/var/lib/juju/agents/unit-juju-lint-test-0/charm/lib/lib_jujulint.py", line 173, in run_auto_lint
    subprocess.check_output([lint_script], stderr=subprocess.STDOUT).decode(
  File "/usr/lib/python3.8/subprocess.py", line 415, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/usr/lib/python3.8/subprocess.py", line 516, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['/usr/local/bin/auto_lint.py']' returned non-zero exit status 1.
unit-juju-lint-test-0: 13:07:18 ERROR juju.worker.uniter.operation hook "config-changed" (via hook dispatching script: dispatch) failed: exit status 1

It turns out that charm upgrade adds an extra line (281):

279 if __name__ == "__main__":
280 main()
281 )

at the end of the script during upgrade which breaks the auto_lint.py script.