def selectCiphers(availableCiphers):
        """
        Choose which ciphers to allow to be negotiated on a TLS connection.

        @param availableCiphers: A L{list} of L{ICipher} which gives the names
            of all ciphers supported by the TLS implementation in use.

        @return: A L{list} of L{ICipher} which represents the ciphers
            which may be negotiated on the TLS connection.  The result is
            ordered by preference with more preferred ciphers appearing
            earlier.
        """

        Choose which ciphers to allow to be negotiated on a TLS connection.

        @param availableCiphers: A L{list} of L{ICipher} which gives the names
            of all ciphers supported by the TLS implementation in use.

        @return: A L{list} of L{ICipher} which represents the ciphers
            which may be negotiated on the TLS connection.  The result is
            ordered by preference with more preferred ciphers appearing
            earlier.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/interfaces.py