urllib.urlopen-bug?

[Markus Krutz]

Hi,
I've got a problem using the urlopen-function from the urllib.
According to the library reference, an IOError-exception should be raised on
two conditions:
1) The connection can't be made.
2) The server returns an error.
On 1) an exceptions is raised, but if I do a
urllib.urlopen("http://www.python.org/nonexistingdocument.html")
no exception is raised, although I think this is a typical 404-Error.
In my opinion this should result in raising an exception...
Any hints on other ways how to check for the existence of a net resource?
(I'm using python v1.5.2)

greetings
Markus