Pyright in VSCodium is confused about type-checking a function assigned to a variable

I'm using VSCodium with the Pyright plugin for Python type checking. I am puzzled why Pyright is not recognizing a variable as type function, when the code works as expected, and entering this code in the Python REPL I can verify action is a function, has a __call__ method, etc.

def pass2() -> None:
    pass

action_set: dict[str, function] = {'pass2': pass2}
action: function = action_set["pass2"]

action()

VSCodium displays this error under action() in line 7: 'Object of type "function" is not callable - Attribute "__call__" is unknown'. But for action on line 5 it shows '(variable) action: function'.