def getMessageSignature(self, message):
        """Return the signature of a message.

        If I am not a sign-all association, the message must have a
        signed list.

        @return: the signature, base64 encoded

        @rtype: str

        @raises ValueError: If there is no signed list and I am not a sign-all
            type of association.
        """
        pairs = self._makePairs(message)
        return oidutil.toBase64(self.sign(pairs))
Return the signature of a message.

        If I am not a sign-all association, the message must have a
        signed list.

        @return: the signature, base64 encoded

        @rtype: str

        @raises ValueError: If there is no signed list and I am not a sign-all
            type of association.