L{IOpenSSLServerConnectionCreator}.

                3. If you really have to, supply a
                   L{twisted.internet.ssl.ContextFactory}.  This will likely be
                   deprecated at some point so please upgrade to the new
                   interfaces.

        @type contextFactory: L{IOpenSSLClientConnectionCreator} or
            L{IOpenSSLServerConnectionCreator}, or, for compatibility with
            older code, anything implementing
            L{twisted.internet.interfaces.IOpenSSLContextFactory}.  See
            U{https://twistedmatrix.com/trac/ticket/7215} for information on
            the upcoming deprecation of passing a
            L{twisted.internet.ssl.ContextFactory} here.

        @param isClient: Is this a factory for TLS client connections; in other
            words, those that will send a C{ClientHello} greeting?  L{True} if
            so, L{False} otherwise.  This flag determines what interface is
            expected of C{contextFactory}.  If L{True}, C{contextFactory}
            should provide L{IOpenSSLClientConnectionCreator}; otherwise it
            should provide L{IOpenSSLServerConnectionCreator}.
        @type isClient: L{bool}

        @param wrappedFactory: A factory which will create the
            application-level protocol.
        @type wrappedFactory: L{twisted.internet.interfaces.IProtocolFactory}
        N)r