converting from perl: variable sized unpack

[Roy Smith]

What's the best way to translate this perl snippet into python:

 ($f1, $f2, $f3, $f4, $f5, $f6) = split ('\s+', $line);

The obvious translation would be:

 [f1, f2, f3, f4, f5, f6] = string.split (line)

but the problem is that line may have fewer than 6 fields on it.  Perl 
handles this smoothly by leaving the "extra" variables undefined, whereas 
python raises a ValueError exception.  What I'd like to do is have the 
extra field variables left as null strings.