def transform_op(self, op):
        """
        Replaces an op with a transformed op.

        :param op: MIL operation
        :return: None
        """
        raise NotImplementedError(
            'Op transformation for quantization mode "{}" not implemented.'.format(self)
        )

        Replaces an op with a transformed op.

        :param op: MIL operation
        :return: None
        
coremltools/converters/mil/mil/passes/defs/quantization.py