def __init__(self, oldStyleContextFactory):
        """
        Construct a L{_ContextFactoryToConnectionFactory} with a
        L{twisted.internet.interfaces.IOpenSSLContextFactory}.

        Immediately call C{getContext} on C{oldStyleContextFactory} in order to
        force advance parameter checking, since old-style context factories
        don't actually check that their arguments to L{OpenSSL} are correct.

        @param oldStyleContextFactory: A factory that can produce contexts.
        @type oldStyleContextFactory:
            L{twisted.internet.interfaces.IOpenSSLContextFactory}
        """
        oldStyleContextFactory.getContext()
        self._oldStyleContextFactory = oldStyleContextFactory

        Construct a L{_ContextFactoryToConnectionFactory} with a
        L{twisted.internet.interfaces.IOpenSSLContextFactory}.

        Immediately call C{getContext} on C{oldStyleContextFactory} in order to
        force advance parameter checking, since old-style context factories
        don't actually check that their arguments to L{OpenSSL} are correct.

        @param oldStyleContextFactory: A factory that can produce contexts.
        @type oldStyleContextFactory:
            L{twisted.internet.interfaces.IOpenSSLContextFactory}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/tls.py