code: def expected(self):
      return cupy.asarray([[1, 2], [3, 4], [5, 6]], self.dtype)
  
imports: import functools
  import re
  from unittest import mock
  import numpy
  import pytest
  import cupy
  from cupy import testing
  from cupy.cuda import runtime
  from cupyx.scipy import sparse
  from cupyx.scipy.sparse import _construct
label_desc: Use image node_id 2 for calling the TestVstack obj's underlying member method code with example usage: obj.expected() and returns: cupy