What is the name of this Python programming style

[Dave Kuhlman]

I'd like to learn more about this style of programming in Python.

In this style or pattern, a high level class is given an instance
(or a class from which it creates an instance), then uses that
instance to perform its tasks.  A user of the higher-level class
can customize the function of that class by implementing or
customizing details in lower-level class.

I've seen it a number of times.  It seems quite useful.  It
provides loose coupling between a higher-level policy class and a
lower-level mechanism or implementation class.  The coupling is
defined by an abstract base class which the lower level class must
implement.  This loose coupling frees the higher-level policy
class from dependency on details in a lower-level mechanism class.

One example of this style is in BaseHTTPServer in the Python
standard library.  The constructor to BaseHTTPServer takes a
handler class as an argument.  The handler class should be
sub-class of BaseHTTPRequestHandler.  So, in this example:

- BaseHTTPServer is the higher-level policy class.

- BaseHTTPRequestHandler defines the interface.  Or should it be
  called the protocol?

- And, the sub-class of BaseHTTPRequestHandler that I'm supposed
  to implement is the lower-level mechanism class.

I think the general name for this is Inversion of Control (IoC).

Can someone tell me if this Python pattern or style has a name
among Pythonistas?

It's not unique to Python, of course, but once again Python seems
very well suited to this pattern or style.

I've been reading about PEAK (http://peak.telecommunity.com/).
PEAK supports this style of programming in a much more complex
way.  Does anyone have some experience with PEAK?  Is the PEAK way
better or more powerful?  Learning the PEAK way seems to require
immersion in a complete Zen of PEAK.  It is pretty opaque to me.
I'd be thankful for a pointer or URL to help me gain a little
understanding.  I've read the tutorial and quite a bit of the PEAK
Wiki.  Is there more somewhere?

Thanks for help.

Dave

-- 
Dave Kuhlman
http://www.rexx.com/~dkuhlman