code: def zip_code():
      
      format = '#####'
      if random.random() >= 0.5:
          format = '#####-####'
  
      result = ''
      for item in format:
          if item == '#':
              result += str(random.randint(0, 9))
          else:
              result += item
  
      return result
docs: Return a random ZIP code, either in `#####` or `#####-####` format.