Accesses :attr:`value` and :attr:`uncert` as a :class:`pwkit.msmt.Uval`.

def uval(self):
        "Accesses :attr:`value` and :attr:`uncert` as a :class:`pwkit.msmt.Uval`."
        from .msmt import Uval
        return Uval.from_norm(self.value, self.uncert)