code: def test_equivalent_to_rbf_interpolator(self):
      seq = Halton(2, scramble=False, seed=np.random.RandomState())
  
      x = seq.random(100)
      xitp = seq.random(100)
  
      y = _2d_test_function(x)
  
      yitp1 = self.build(x, y)(xitp)
  
      yitp2 = []
      tree = cKDTree(x)
      for xi in xitp:
          _, nbr = tree.query(xi, 20)
          yitp2.append(RBFInterpolator(x[nbr], y[nbr])(xi[None])[0])
  
      assert_allclose(yitp1, yitp2, atol=1e-8)
  
imports: import pickle
  import pytest
  import numpy
  from numpy.linalg import LinAlgError
  from numpy.testing import assert_allclose, assert_array_equal
  from scipy.stats.qmc import Halton
  from scipy.spatial import cKDTree
  from scipy.interpolate._rbfinterp import _AVAILABLE, _SCALE_INVARIANT, _NAME_TO_MIN_DEGREE, _monomial_powers, RBFInterpolator
  from scipy.interpolate import _rbfinterp_pythran
label_desc: Use image node_id 2 for calling the TestRBFInterpolatorNeighbors20 obj's underlying member method code with example usage: obj.test_equivalent_to_rbf_interpolator() without return types