issue2551033: prevent reverse engineering hidden data by using etags as an oracle to identify when the right data has been guessed. Identified by Joseph Myers who also suggested remediation methods. Implemented John Rouillard.

try:
    # Python 3+.
    from xmlrpc import client, server
    server.SimpleXMLRPCDispatcher
except (ImportError, AttributeError):
    # Python 2.
    import xmlrpclib as client
    import SimpleXMLRPCServer as server