src/transformers/onnx/config.py/OnnxConfig/inputs
class OnnxConfig:    def inputs(self) -> Mapping[str, Mapping[int, str]]:
        """
        Mapping containing the axis definition of the input tensors to provide to the model

        Returns:
            For each input: its name associated to the axes symbolic name and the axis position within the tensor
        """
        raise NotImplementedError()