def _isSecure(self):
        """
        Returns L{True} if this channel is using a secure transport.

        @returns: L{True} if this channel is secure.
        @rtype: L{bool}
        """
        # A channel is secure if its transport is ISSLTransport.
        return ISSLTransport(self.transport, None) is not None

        Returns L{True} if this channel is using a secure transport.

        @returns: L{True} if this channel is secure.
        @rtype: L{bool}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/_http2.py