code: def test_argmax_nan_imag(self, xp, dtype):
      a = xp.array(
          [float("nan") * 1.0j, 1.0j, -1.0j], dtype, order=self.order
      )
      return a.argmax()
  
imports: import unittest
  import numpy
  import pytest
  import cupy
  import cupy._core._accelerator
  from cupy._core import _cub_reduction
  from cupy import testing
label_desc: Use image node_id 41 for calling the TestArrayReduction obj's underlying member method code with example usage: obj.test_argmax_nan_imag(xp, dtype) and returns: a