Fix mypy error in channels.py

[dougthor42]

This technically fixes the mypy error seen in channels.py, but I'm not sure if it's the best fix. IMO it simply masks the symptom rather than fixes the root cause. I think more refactoring and architecture changes might be needed to fix the root issue.

$ mypy pyvisa_sim/
pyvisa_sim/channels.py:199: error: Argument 1 to "set_value" of "Property" has incompatible type "Union[Any, Dict[Any, Any]]"; expected "str"  [arg-type]

I also move the type hints to component.Component.__init__ as that's common practice.

One of the issues is that the stringparser library doesn't have type annotations, so mypy sets parser to Any here:

pyvisa-sim/pyvisa_sim/channels.py

Line 187 in b0c2282

for name, parser, response, error_response in self._setters:

and then parsed to Any here:

pyvisa-sim/pyvisa_sim/channels.py

Line 189 in b0c2282

parsed = parser(q)

From there, the isinstance statement end up doing type narrowing to Dict[Any, Any] which then gets Union'd with Any from before.

The issue is that the self.set_value function doesn't accept Any. Based on my (possibly flawed) understanding of the code, it looks like it's safe enough to just convert to a string before calling set_value. So that's what I do.

In addition, I ran a temporary backport of this change to v0.5.1 and ran my tests for a separate project that uses pyvisa-sim, and those still ran OK so... I guess it's OK?

[MatthieuDartiailh]

I personally prefer to avoid crowding type annotations in init so I would appreciate if you could revert your second commit. Additionally, while we are dealing with linter errors could you address the black issues ?

[dougthor42]

Done.

Not sure why pre-commit didn't catch the black issue... ah well, a problem for another time.