Suppose that you are writing a Python module that has exceptions as partof its interface, and you want them to actually be useful to people. Fromthe perspective of a sometimes grumpy user of module exceptions, here ismy opinions on what you should do:

• all exceptions that you expect people to actually catch should descendfrom a common ancestor class, so that people can just do ' exceptYourException, e: ' and be done with it.

  If you have an exception you raise for internal errors and otherimpossible situations

It's intuitively obvious how (volatile) disk write caches can result inyou losing data in files if something goes wrong; you wrote data, thedisk told your program it had been written, the disk lost power, andthe data vanishes. But it may be less obvious how this can result incorrupted or destroyed filesystems and thus why you need (working) cacheflush operations even just to keep your filesystems intact (never mindwhat user level programs may want).

Consider a filesystem where you have two