$ python lala.py 
Traceback (most recent call last):
  File "lala.py", line 6, in <module>
    cache.open(None)
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 164, in open
    self._cache = apt_pkg.Cache(progress)
SystemError: E:The package cache was built for different architectures:  vs i386, W:You may want to run apt-get update to correct these problems, E:The package cache file is corrupted