def __conform__(self, interface):
        """
        Convert this L{CertBase} into a provider of the given interface.

        @param interface: The interface to conform to.
        @type interface: L{zope.interface.interfaces.IInterface}

        @return: an L{IOpenSSLTrustRoot} provider or L{NotImplemented}
        @rtype: L{IOpenSSLTrustRoot} or L{NotImplemented}
        """
        if interface is IOpenSSLTrustRoot:
            return OpenSSLCertificateAuthorities([self.original])
        return NotImplemented

        Convert this L{CertBase} into a provider of the given interface.

        @param interface: The interface to conform to.
        @type interface: L{zope.interface.interfaces.IInterface}

        @return: an L{IOpenSSLTrustRoot} provider or L{NotImplemented}
        @rtype: L{IOpenSSLTrustRoot} or L{NotImplemented}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/_sslverify.py