Not all developers on all code, but N developers on any given piece of code, where N should be greater than 1. Why were you asked to do the review? Is N equal t

Not all developers on all code, but N developers on any given piece of code, where N should be greater than 1. Why were you asked to do the review? Is N equal to 1 so there is nobody besides the author who has the expertise needed to do the review? That's a good opportunity to start the process of raising N to 2. Is it because N is equal to 2, but the other person is out on vacation? Better start working on getting N to 3 then!