def __init__(self, privateKeyFileName, certificateFileName,
                 sslmethod=SSL.SSLv23_METHOD, _contextFactory=SSL.Context):
        """
        @param privateKeyFileName: Name of a file containing a private key
        @param certificateFileName: Name of a file containing a certificate
        @param sslmethod: The SSL method to use
        """
        self.privateKeyFileName = privateKeyFileName
        self.certificateFileName = certificateFileName
        self.sslmethod = sslmethod
        self._contextFactory = _contextFactory

        # Create a context object right now.  This is to force validation of
        # the given parameters so that errors are detected earlier rather
        # than later.
        self.cacheContext()

        @param privateKeyFileName: Name of a file containing a private key
        @param certificateFileName: Name of a file containing a certificate
        @param sslmethod: The SSL method to use
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/ssl.py