I don't know. Some packages just don't work with type checkers, e.g. Django.
Django has a community stubs project, are you using it?
the stubs can only do so much. There's so much magic and inferred properties that a type checker will never be able to fill in alone
Does django-stubs work with other type checkers than Pyright?
Stubs are a standard python feature (PEP 561) so I'd expect them to work with any type checker which supports stubs, which should be all of them (as much of the ecosystem is typed via stubs).
Is it not that he used the "--suppress-errors" flag yet it did not ignore the errors?
It's hard to tell. Other similar options in other commands can mean things like "exit with status 0 even if errors are detected". Without installing pyrefly, I'm not sure what that flag's supposed to do. It's not documented on their site.
It adds a comment to suppress the error above each line in your codebase that causes an error, but it reports the errors before doing that, so you can only see the result after you re-run `pyrefly check`.
Oh! That's nifty. It leaves you with a baseline so you can stop making new mistakes, and gives you something to grep for when you want to fix existing ones.