ssh popen stalling on password redirect output?

[supercomputer at gmail.com]

I have a script that I cycle through nodes connect to them and run
uptime to get some information.  I run the script as root so it doesn't
require a password on the rest of the nodes.  It does however barf on
the nodes that are having trouble and require a different password.  Is
there an easy way to skip these nodes?  Maybe redirect the password
prompt to stdout or stderr or even skip them?

Thanks in advance here is the current script.

info=os.popen('ssh node208 uptime')
sys.stderr=info
sys.stderr.write(info)

I'm very new to python if you could give me a link to an article that
would also be helpful.  The documentation on python is very hard to
find as compared with php.net's php documentation.