extending methods ?

[Arnd Baecker]

Hi,

the summary of my question is:
is there a way to append commands to a method inherited from
another class?

More verbose: Assume the following situation that I have
a class class_A with several methods.
In each of these methods quite a few computations take place
and several variables are defined.
Now I would like to extend this class to a class_B.
However, instead of overriding a method completely,
I would like to extend the method by basically adding
further commands at the end.

Eg., the code could look like:

class class_A:
    def method1(self,x):
        y=5*x+1                 # create a variable


class class_B(class_A):
    appendto method1(self,x):
        print y                 # use variable defined in class_A


I.e. Effictively class_B should "look" like:

class class_B(class_A):
    def method1(self,x):
        y=5*x+1                 # create a variable
        print y                 # use the variable

Instead of this, one could in principle
store all variables defined in
method1 of class_A, eg. with self.y=y
and call in class_B the method1 of class_A.
However, with several variables and several methods
the code will not look nice.
(also efficiency is a bit of concern - presumably it shouldn't -
 to me here as in my application the methods
 are used to plot dots, circles, triangles etc.
 so that speed is really important)

So is there a way to extend methods in the above sense
or is there a better (more pythonic ? ;-) approach to what I want?

Many thanks in advance.

Arnd

P.S.: Sorry if I messed up things on the OO side
      (I am a real new-comer to this ...;-).