code: def test_getitem(self, xp, dtype, order):
      a = testing.shaped_arange(self.shape, xp, dtype, order)
      return a.flat[self.index]
  
imports: import unittest
  import warnings
  import numpy
  import pytest
  import cupy
  from cupy import testing
label_desc: Use image node_id 1 for calling the TestFlatiterSubscript obj's underlying member method code with example usage: obj.test_getitem(xp, dtype, order) and returns: a