Summary: Constrain format of classname and document Define the format of a valid classname. Updated design doc, function doc and glossary to document format. Error message for case where we have a redefinition of a classname now says why ValueError is raised since we are raising ValueError for incorrect classname format as well. Tests for all cases including verification of cause for ValueError exceptions.

try:
    # Python 3+.
    from xmlrpc import client, server
    server.SimpleXMLRPCDispatcher
except (ImportError, AttributeError):
    # Python 2.
    import xmlrpclib as client  # noqa: F401
    import SimpleXMLRPCServer as server