def get_io_elem_type(self, io_name: str) -> Optional[int]:
        """Get the element type of an input/output.

        :param io_name: name of the input/output.
        :return: element type of the input/output.
        """
        if self.is_initializer(io_name):
            return self.get_initializer_proto(io_name).data_type

        tensor_type = self._get_vi_tensor_type(io_name)
        return tensor_type.elem_type if tensor_type else None
Get the element type of an input/output.

        :param io_name: name of the input/output.
        :return: element type of the input/output.
        
olive/passes/onnx/onnx_dag.py