def get_concrete_fn(model, input_signature, **kwargs):
    """Get the `tf.function` associated with the model."""
    if backend.backend() == "jax":
        kwargs = _check_jax_kwargs(kwargs)
    export_archive = ExportArchive()
    export_archive.track_and_add_endpoint(
        DEFAULT_ENDPOINT_NAME, model, input_signature, **kwargs
    )
    if backend.backend() == "tensorflow":
        export_archive._filter_and_track_resources()
    return export_archive._get_concrete_fn(DEFAULT_ENDPOINT_NAME)
Get the `tf.function` associated with the model.
keras/src/export/onnx.py