code: def test_linear_xi1d(self):
      points, values = self._get_sample_4d_2()
      interp = RegularGridInterpolator(points, values)
      sample = cp.asarray([0.1, 0.1, 10.0, 9.0])
      wanted = 1001.1
      assert_array_almost_equal(interp(sample), wanted)
  
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 6 for calling the TestRegularGridInterpolator obj's underlying member method code with example usage: obj.test_linear_xi1d() without return types