There is no default_factory for Param objects?

Param
#1

If I want to define a dataclass field that chooses a value via a zero-argument lambda, I can do the following:

marketer_id = itertools.count(1)

@dataclass
class Marketer:
    id: int = field(default_factory=lambda: next(marketer_id))

But it seems I must do the following in Param, correct?

class Marketer(Parameterized):
    id = Number()

    def __init__(self, **params):
        super().__init__(**params)
        self.id = next(marketer_id)