How to Generate a List of Possible Words in a Phone Number in Python

Example, if we type 2 -> 2 -> 3. The we have can have words like "AAD", "AAE", "AAF", etc.

#!/usr/bin/env python

numbers = {"2" : ["A", "B", "C"],
           "3" : ["D", "E", "F"],
           "4" : ["G", "H", "I"],
           "5" : ["J", "K", "L"],
           "6" : ["M", "N", "O"],
           "7" : ["P", "Q", "R"],
           "8" : ["S", "T", "U"],
           "9" : ["V", "W", "X"],
           "0" : ["Y", "Z"]}

def generate(input_list):
    return gen(input_list, 0, "")

def gen(input_list, index, n):
    if index > len(input_list)-1: return [n]
    output_list = []
    for i in input_list[index]:
        index += 1
        for x in numbers[i]:
            tmp = gen(input_list, index, x)
            for t in tmp:
                output_list.append(n + t)
    return output_list
    
if __name__ == "__main__":
    for i in generate(["2", "4", "3", "6"]): print i