old_contents: # Python 2/3 compatibility
  
  try:
      from urllib.error import URLError, HTTPError
      from urllib.request import urlopen, urlretrieve
      from io import BytesIO
  
      def bytes_decode(bytes_, encoding='utf-8'):
          return bytes_.decode(encoding)
  except ImportError:
      # Python 2.X
      from urllib2 import URLError, HTTPError, urlopen
      from urllib import urlretrieve
      from StringIO import StringIO as BytesIO
      
      def bytes_decode(bytes_, encoding='utf-8'):
          return bytes_
  
  try:
      from functools import lru_cache
  except ImportError:
      # Python 2.X: function not available
      def lru_cache(maxsize=128, typed=False):
          return lambda y: y
  
new_contents: # Python 2/3 compatibility
  
  try:
      from urllib.error import URLError, HTTPError
      from urllib.request import urlopen, urlretrieve
      from io import BytesIO
  
      def bytes_decode(bytes_, encoding='utf-8'):
          return bytes_.decode(encoding)
  except ImportError:
      # Python 2.X
      from urllib2 import URLError, HTTPError, urlopen
      from urllib import urlretrieve
      from StringIO import StringIO as BytesIO
  
      def bytes_decode(bytes_, encoding='utf-8'):
          return bytes_
  
subject: remove unused Py2/3 compat