Start incorporating type checker to GUI file

[ThePhilgrim]

No description provided.

[Akuli]

Why second review: I mypyed and found from problems from upwatch.py.

[Akuli]

Usually json_content["Job Posts"] can be None, but not in this function. Unfortunately mypy isn't clever enough to notice that, and we need to tell that to mypy manually. See python/mypy#4245

Suggested change

	old_job_urls = [job_post["Job Post URL"] for job_post in json_content["Job Posts"]]
	assert json_content["Job Posts"] is not None
	old_job_urls = [job_post["Job Post URL"] for job_post in json_content["Job Posts"]]

[ThePhilgrim]

Can you please specify why Mypy even needs to notice that it cannot be None? We already told mypy that "it's optionally JobPost" This means that it will be 1 or 0, and in this function it will just always be 1. Why does mypy need more info?

[ThePhilgrim]

Also, this suggestion is marked as outdated for some reason. I cannot "commit suggestion", and it is not implemented neither in type_checker or main.

[Akuli]

There's also this code, but unfortunately I cant add a review comment at it:

        job_post_dict = {
            "Job Title": job_title,
            "Payment Type": job_payment_type,
            "Budget": job_budget,
            "Job Description": job_description,
            "Job Post URL": "https://upwork.com" + job_post_url,
        }

The problem is that mypy sees this as a dict with string keys and Any values, instead of noticing that this is in fact a JobPost. This leads to error like this:

upwatch.py:202: error: Argument 2 has incompatible type "List[Dict[str, Any]]"; expected "Optional[JobPost]"

To fix this, we can add a type hint : JobPost when defining the variable:

        job_post_dict: JobPost = {
            ...
        }