speaking_list.py

# Using the OS X "say" command to demo inheritance
# Thanks to Simon Willison for inspiration: http://gist.github.com/267147

import subprocess

def say(s):
    subprocess.call(['say', str(s)])

class SpeakingList(list):
    """This custom list speaks (if you're on OS X). Amazing!"""
    def __init__(self):
        super(SpeakingList, self).__init__()
        say("A new list is born!")
    
    def append(self, value):
        super(SpeakingList, self).append(value)
        say("Added: %s" % value)

    def __len__(self):
        l = super(SpeakingList, self).__len__()
        say("The list length is %s" % l)
        return l