How to make List in python dataclass that can accept multiple different types?

I am creating new data class in python.

@dataclass
class User(Mixin):
  id: int = None
  items: List[DefaultItem] = None

This items is array of DefaultItem objects but I need this to be multiple possible objects like:

items: List[DefaultItem OR SomeSpecificItem OR SomeOtherItem] = None

How can I do something like this in python?

>Solution :

You can use typing.Union for this.

items: List[Union[DefaultItem, SomeSpecificItem, SomeOtherItem]] = None

And if you are on Python 3.10, they’ve added a convenient shorthand notation:

items: list[DefaultItem | SomeSpecificItem | SomeOtherItem] = None

Also just as a note: If items is allowed to be None, you should mark the type as Optional.