code: def test_nanstd_out(self, xp, dtype):
      a = testing.shaped_random((10, 20, 30), xp, dtype)
      z = xp.zeros((20, 30))
  
      if a.dtype.kind not in "biu":
          a[1, :] = xp.nan
          a[:, 3] = xp.nan
  
      xp.nanstd(a, axis=0, out=z)
      return z
  
imports: import math
  import numpy
  import pytest
  import cupy
  from cupy import testing
label_desc: Use image node_id 4 for calling the TestNanVarStdAdditional obj's underlying member method code with example usage: obj.test_nanstd_out(xp, dtype) and returns: z