code: def _sample_2d_data(self):
      x = cp.array([0.5, 2.0, 3.0, 4.0, 5.5, 6.0])
      y = cp.array([0.5, 2.0, 3.0, 4.0, 5.5, 6.0])
      z = cp.array(
          [
              [1, 2, 1, 2, 1, 1],
              [1, 2, 1, 2, 1, 1],
              [1, 2, 3, 2, 1, 1],
              [1, 2, 2, 2, 1, 1],
              [1, 2, 1, 2, 1, 1],
              [1, 2, 2, 2, 1, 1],
          ]
      )
      return x, y, z
  
imports: import pytest
  import cupy
  from cupy.testing import assert_allclose, assert_array_equal, assert_array_almost_equal
  from cupy_backends.cuda.api import runtime
  from pytest import raises
  from cupyx.scipy.interpolate import RegularGridInterpolator, interpn
label_desc: Use image node_id 1 for calling the TestInterpN obj's underlying member method code with example usage: obj._sample_2d_data() and returns: x,  y,  z