code: def test_iamax(self):
      x = self._make_random_vector()
      ref = cupy.argmax(cupy.absolute(x.real) + cupy.absolute(x.imag))
      out = self._make_out("i")
      res = cublas.iamax(x, out=out)
      self._check_pointer(res, out)
      # Note: iamax returns 1-based index
      cupy.testing.assert_array_equal(res - 1, ref)
  
imports: import numpy
  import pytest
  import cupy
  from cupy import cublas
  from cupy import testing
label_desc: Use image node_id 6 for calling the TestLevel1Functions obj's underlying member method code with example usage: obj.test_iamax() without return types