Python Address Book

#! /usr/bin python
""" Two simple python function for reading an writing a dictionary
of list of length 4, for cs150 assignment
"""

import sys


def read():
    # reading in the diction using argv[1] as the name of the file
    if len(sys.argv)<2:
        print """ Sorry you must give the name of the file on the command line"""
        sys.exit(2)
    dict_file_name = sys.argv[1]
    try:
        dict_file = open(dict_file_name,"r")
    except IOError:
        print "No data file", dict_file_name, "will be created at the end of the program"
        return {}
    addressdict={}
    line = dict_file.readline()
    while line:
        nickname = line[:-1]
        datastring = dict_file.readline()
        if not datastring:
            print "Badly formated data file, extra lines"
        else:
            data = eval(datastring)
            if type(data) != type([]) or len(data)!= 4:
                print "Badly formated data line:", datastring
            else:
                addressdict[nickname]=data
        line = dict_file.readline()
    
    dict_file.close()
    return addressdict

def write(addressdict):
    dict_file_name = sys.argv[1]
    dict_file = open(dict_file_name,"w")
    for nickname in addressdict.keys():
        dict_file.write(str(nickname)+"\n")
        dict_file.write(repr(addressdict[nickname])+"\n")
    dict_file.close()