def _normalize_dtype(dtype: _torch.dtype) -> _torch.dtype:
        """
        PyTorch export quantizer only supports uint8 and int8 data types,
        so we map the quantized dtypes to the corresponding supported dtype.
        """
        dtype_map = {
            _torch.quint8: _torch.uint8,
            _torch.qint8: _torch.int8,
        }
        return dtype_map.get(dtype, dtype)

        PyTorch export quantizer only supports uint8 and int8 data types,
        so we map the quantized dtypes to the corresponding supported dtype.
        
coremltools/optimize/torch/quantization/_annotation_config.py