[Tutor] Dumb Subclassing question

[Andy Baker]

Hi all,

Please bear with me as I might have this hopelessly muddled. My attempts to
learn OO through simple cases never turn out that simple...

I, like everyone else in the universe, am writing a prog to manipulate and
organize mp3's...

The idea was to base it on Jason Orendorff 'path' module
(http://www.jorendorff.com/articles/python/path/) and add some methods to
the path object that are mp3 specific.

So I subclass the 'path' object as 'mp3path' and add some of my own methods.

Several of the methods in the original 'path' return more path objects so
the methods I inherit from path also return path objects. I want my new
methods to act on the returned objects.

An example:

myPath.files() returns a list of path objects

I have added a new method ID3tag to my MP3path class
I want myMP3path.files to return a list of objects that can still access my
ID3tag method.

Options that have occurred to me:

1. Override every method in 'path' that returns paths with a wrapper method
that converts them into mp3paths. This seems ugly, boring and pointless.
2. Forget subclassing and add methods directly into the path module source.
This will be bad when a new version of 'path' comes along and also seems
like cheating.
3. Add methods dynamically into the path object. (Is this 'decorator'?) I
looked at the instancemethod function in the standard library 'new' module
and this adds methiods to instances but not to classes so I would have to do
this for every instance. 
4. Forget the whole OO thang and just use functions. (Looking more
attractive by the minute ;-)

Am I being thick here? What's the proper way to do this? I can see a similar
situation happeneing if I ever subclass 'string' or suchlike.