Does Python have "not a number" floating point values?

[owen at astroNOJNK.washington.edu.invalid.bbs]

Does Python support any sort of floating point "not a number" (e.g. IEEE
infinity)?

I realize I can just use None, but it's convenient to be able to tell
the difference between inifinity and undefined, and to be able to
perform a computation that may fail without raising an exception.

-- Russell