Protcol Buffers - Python - Issue with tutorial -

context

• i'm working through tutorial: https://developers.google.com/protocol-buffers/docs/pythontutorial
• i've created files copy , pasting above tutorial

issue

when run below file in python launchernothing happens:

#! /usr/bin/python  import addressbook_pb2 import sys  # iterates though people in addressbook , prints info them. def listpeople(address_book):   person in address_book.person:     print "person id:", person.id     print "  name:", person.name     if person.hasfield('email'):       print "  e-mail address:", person.email      phone_number in person.phone:       if phone_number.type == addressbook_pb2.person.mobile:         print "  mobile phone #: ",       elif phone_number.type == addressbook_pb2.person.home:         print "  home phone #: ",       elif phone_number.type == addressbook_pb2.person.work:         print "  work phone #: ",       print phone_number.number  # main procedure:  reads entire address book file , prints #   information inside. if len(sys.argv) != 2:   print "usage:", sys.argv[0], "address_book_file"   sys.exit(-1)  address_book = addressbook_pb2.addressbook()  # read existing address book. f = open(sys.argv[1], "rb") address_book.parsefromstring(f.read()) f.close()  listpeople(address_book) 

result:

question

• what steps should take work out issue?

that's not "nothing happens". got error message showing didn't call program correctly. specifically, didn't pass address book file use.