Add type annotations [WIP]

[sveinse]

With reference to discussion in #358, this PR adds typing annotations to canopen.

As of today, this branch is still work in progress and the annotation is not yet complete.

mypy is the primary type checker, however as [my] development is done in VSCode, the code is linted against pyright/pylance.

Closes #358

[christiansandberg]

What happens if you add mypy to GitHub actions (.github/workflows/pythonpackage.yml)? Does it pass or are there more things that need fixing?

[sveinse]

There are still some mypy issues remaining:

canopen\objectdictionary\__init__.py:527: error: Invalid index type "List[int]" for "Dict[str, List[int]]"; expected type "str"  [index]
canopen\objectdictionary\__init__.py:538: error: Invalid index type "List[int]" for "Dict[str, List[int]]"; expected type "str"  [index]
canopen\variable.py:194: error: Incompatible types in assignment (expression has type "List[int]", variable has type "range")  [assignment]
canopen\variable.py:208: error: Argument 1 to "iter" has incompatible type "Dict[str, List[int]]"; expected "SupportsIter[Iterator[int]]"  [arg-type]
canopen\pdo\base.py:100: error: Cannot find implementation or library stub for module named "canmatrix"  [import]
canopen\pdo\base.py:100: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
canopen\pdo\base.py:115: error: Incompatible types in assignment (expression has type "float", variable has type "Optional[int]")  [assignment]
canopen\pdo\base.py:117: error: Incompatible types in assignment (expression has type "float", variable has type "Optional[int]")  [assignment]
canopen\objectdictionary\eds.py:54: error: "ObjectDictionary" has no attribute "__edsFileInfo"  [attr-defined]
canopen\objectdictionary\eds.py:321: error: "Variable" has no attribute "default_raw"; maybe "default"?  [attr-defined]
canopen\objectdictionary\eds.py:322: error: "Variable" has no attribute "default_raw"; maybe "default"?  [attr-defined]
canopen\objectdictionary\eds.py:330: error: "Variable" has no attribute "value_raw"  [attr-defined]
canopen\objectdictionary\eds.py:427: error: "ObjectDictionary" has no attribute "__edsFileInfo"  [attr-defined]
Found 12 errors in 4 files (checked 28 source files)

These are related to Bits, PdoBase.export() which depend on unknown canmatrix, and the injection of __edsFileInfo attr in objectdictionary.eds.import_eds(). Ref my long comment in #358 , these are questions I need some guidance/discussion on how to solve.

It is probably a great idea to incorporate mypy checks into GH actions workflow, but it is not yet implemented.

[sveinse]

I don't plan to implement this PR. Instead the type annotations will be split up into multiple PRs of suitable chunks which makes it easier to review. Closing this PR.