[Tutor] metaclass question

[Kim Branson]

Hi i'm interested in implementing a factoryclass in python

What i'd like to do is have my factoryClass produce an instance of a  
class with some methods defined in arguments to the factory class.

The classes that are produced have many common methods, but a single  
unique method. This method actually is a series of calls to a c++ api.
Depending on what we are doing with the produced class, i'd like the  
unique method to call api function A, or api function B etc.   
Alternatively the unique method might call A and the B and return a  
dict of the results.

I'm doing this because i'd like all my produced class instances to  
simply have  a calculateResults method which will then go and do the  
right thing.  I don't want to set some values in the init, like A==  
True  and have a if A: call methodA etc statement.

I'm not sure if a factory class is the best way to solve this  
problem, but i can see future cases where the unique function will  
need to do many things with intermediate results before returning the  
results dict.   i think a factory class might be the best way of  
ensuring an extensible design.

So whats the best way to do this. I have found many references to  
creating a class with __metaclass__ = SomeMetaClass,  but i don't see  
how one can pass arguments to the meta class.

An alternative might be to have a class that operates on an existing  
instance and adds the correct method, but this seems slightly clunky,  
and is probably not the python way


Cheers

Kim