#!/usr/bin/python
# from the python tutorial

def invert(table):
    index = {}                # empty dictionary
    for key in table.keys():
        value = table[key]
        if not index.has_key(value):
            index[value] = [] # empty list
        index[value].append(key)
    return index

phonebook = {'guido': 4127, 'sjoerd': 4127, 'jack': 4098}
phonebook['dcab'] = 4147   
inverted_phonebook = invert(phonebook)
print inverted_phonebook