pub trait CheckedAddWithExtra<Rhs = Self, Extra = ()> {
    type Output;
    // Required method
    fn checked_add_with_extra(
        self,
        rhs: Rhs,
        extra: Extra,
    ) -> Option<Self::Output>;
}pub trait CheckedAddWithExtra<Rhs = Self, Extra = ()> {
    type Output;
    // Required method
    fn checked_add_with_extra(
        self,
        rhs: Rhs,
        extra: Extra,
    ) -> Option<Self::Output>;
}