old_contents: 
  
  def as_int(value):
      try:
          return int(value)
      except ValueError:
          return None
  
new_contents: 
  
  def as_int(value):
      try:
          return int(value)
      except ValueError:
          return None
  
  
  def urljoin(*parts):
      url = parts[0]
      for p in parts[1:]:
          if url[-1] != '/':
              url += '/'
          url += p
      return url
  
subject: Add url join which serves our needs