python 2.3.4 for windows: float("NaN") throws exception

[asmirnov1234567890 at yahoo.com]

Hi

my python 2.3.4 for windows refuse to execute line float("NaN"). It
says:

>>> float("NaN")
Traceback (most recent call last):
File "<stdin>", line 1, in ?
ValueError: invalid literal for float(): NaN

The same line works as expected on Linux and Solaris with python 2.3.4.
Could anybody explain what is possibly wrong here? is it bug or
feature?

Andrei