I would like to avoid a PyCharm warning from unrecognized attributes. This is happening because I type-hint a base class in the function argument, however the function itself uses attributes from derived classes.

More concretely, this is my code structure:

@dataclass
class Base

@dataclass
class Derived (Base)
    a: str = 'a'

class Foo:
    def __init__(self, obj: Base):
        self._obj = obj
    def geta(self):
        return self._obj.a

The last line gives me the following warning:

Unresolved attribute reference a for class Base.

Is there any way I can avoid this warning by using type-hinting?

One potential solution is to import Union from the typing module and simply add the list of derived classes in the type hint, however I am expecting quite a few derived classes so I'd rather avoid that.