Some median Python NaNsense

Say you have a survey, and you did not get numbers from some people because they cannot be reached, and from others, because they refuse to answer. Suppose you want to deal with these two types of "no value" differently.
Should Python support it too?

It seems to me it's a task for a particular library (in an object-oriented language!) to design a type that accurately represents its domain, rather than blindly use (and abuse) a native type that mostly, but not completely, does the job.
Then under the hood optimize it to your heart's content...