code: def test_external_op():
      # check if operator already exists
      if hasattr(mx.nd, "min_ex"):
          raise MXNetError("Operator already loaded")
  
      lib = "libexternal_lib.so"
      fname = os.path.join(
          base_path, "example/extensions/lib_external_ops/build/" + lib
      )
      if not os.path.exists(fname):
          raise MXNetError(f"library {lib} not found ")
  
      fname = os.path.abspath(fname)
      mx.library.load(fname, False)
  
      # execute operator
      try:
          mx.nd.min_ex()
      except:
          raise MXNetError("Operator not loaded successfully")
  
file_path: mxnet/tests/python/gpu/test_extensions_gpu.py
imports: import os
  import platform
  import mxnet
  import numpy
  from mxnet import nd
  from mxnet.gluon import nn
  from mxnet.base import MXNetError
  from mxnet.test_utils import download, is_cd_run, assert_almost_equal, default_device
  import pytest
label_desc: Use image node_id 3 for calling a global function with example usage: test_external_op() without return types