new_contents: import addressbook_pb2
  import sys
  
  person = addressbook_pb2.Person()
  person.id = 1234
  person.name = "John Doe"
  person.email = "jdoe@example.com"
  phone = person.phone.add()
  phone.number = "555-4321"
  phone.type = addressbook_pb2.Person.HOME
  
  f = open('data.bin', 'wb')
  f.write(person.SerializeToString())
  f.close()
  
subject: add a python script to generate a test data file