JarFile.class_count fails

[SpaceManiac]

JarFile.class_count attempts to take the len() of a generator object.

$ python
Python 2.7.3 (default, Apr 10 2012, 23:31:26) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from jawa.jf import JarFile
>>> JarFile().class_count
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "c:\Python27\lib\site-packages\jawa\jf.py", line 54, in class_count
    return len(p for p in self.namelist if p.endswith('.class'))
TypeError: object of type 'generator' has no len()

Suggestion: replace line 54 of jf.py with:
return len([p for p in self.namelist if p.endswith('.class')])