I need to call a certain method on the argument of an union when used a member of a class which in
I have a data class having as member a list of objects of another class having as member an object of type Optional[CustomType] as member, and I need to call a method of CustomType class on that member, only when the member is not None.
Even if such check is explicitly performed, mypy still complains about the missing attribute of the item None of the CustomType | None union.