Invalid `type: ignore` style when checking with mypy

[jamescw19]

The jsonschema module has 3 type: ignore comments that are not in PEP484 format. This results in the following error when running mypy where referencing has been imported:

$ mypy my_package
/usr/local/lib/python3.8/dist-packages/referencing/jsonschema.py:432: error: Invalid "type: ignore" comment
/usr/local/lib/python3.8/dist-packages/referencing/jsonschema.py:474: error: Invalid "type: ignore" comment
/usr/local/lib/python3.8/dist-packages/referencing/jsonschema.py:505: error: Invalid "type: ignore" comment
Found 3 errors in 1 file (errors prevented further checking)

The error produced is the same as reported here. However, newer versions of mypy do not fix the issue, as the style is not correct.

These can't be ignored with the mypy ignore_errors = True flag, because these are fatal errors that do not allow mypy to run over the rest of the codebase.

From what I can tell, the error messages just need an extra # after the error code to allow mypy to pass

[Julian]

Hi there -- pyright (which is what's used here in the repo) has no issue with these, which is why CI passes -- I'm happy to merge a PR to change the syntax, though ideally one that also then adds a minimal mypy setup which would have failed for this, otherwise it's hard to promise it won't happen again.

[jamescw19]

It looks like this specific error only occurs in mypy<0.990, so in my setup updating mypy should be fine. I don't think it's worth a mypy check against v0.982 just for this case. But there are of course other blocking mypy errors, so it might be good to make this change, and add the minimal mypy setup just to be safe? What do you think @Julian?

[jamescw19]

I opened the PR anyway 🙂