code: def _get_sample_4d(self):
      # create a 4-D grid of 3 points in each dimension
      points = [(0.0, 0.5, 1.0)] * 4
      values = cp.asarray([0.0, 0.5, 1.0])
      values0 = values[:, cp.newaxis, cp.newaxis, cp.newaxis]
      values1 = values[cp.newaxis, :, cp.newaxis, cp.newaxis]
      values2 = values[cp.newaxis, cp.newaxis, :, cp.newaxis]
      values3 = values[cp.newaxis, cp.newaxis, cp.newaxis, :]
      values = values0 + values1 * 10 + values2 * 100 + values3 * 1000
      return points, values
  
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 TestRegularGridInterpolator obj's underlying member method code with example usage: obj._get_sample_4d() and returns: points,  values