code: def ref_non_max_suppression(
      boxes,
      scores,
      center_point_box,
      max_output_boxes_per_class,
      iou_threshold,
      score_threshold,
  ):
      model = make_onnx_model(
          boxes.shape, scores.shape, center_point_box
      )
      session = ort.InferenceSession(
          model, providers=["CPUExecutionProvider"]
      )
      outputs = session.run(
          None,
          {
              "boxes": boxes,
              "scores": scores,
              "max_output_boxes_per_class": [
                  max_output_boxes_per_class
              ],
              "iou_threshold": [iou_threshold],
              "score_threshold": [score_threshold],
          },
      )
      return outputs[0]
  
file_path: nnabla/python/test/function/test_onnx_non_max_suppression.py
imports: import pytest
  import numpy
  import nnabla
  import nnabla.functions
  from nbla_test_utils import list_context
  from nnabla.testing import assert_allclose
label_desc: Use image node_id 2 for calling a global function with example usage: ref_non_max_suppression(boxes, scores, center_point_box, max_output_boxes_per_class, iou_threshold, score_threshold) and returns: outputs