NaN is not the same as None/null, and using it that way is asking for bugs.
None/null is for missing/unknown values (which may be a reasonable thing in your domain), while NaN is for the result of an illegal/undefined operation (which is definitely a bug, such as division by 0).
None/null is for missing/unknown values (which may be a reasonable thing in your domain), while NaN is for the result of an illegal/undefined operation (which is definitely a bug, such as division by 0).