code: def test_pickleable(self):
      # Make sure we can pickle and unpickle the interpolant without any
      # changes in the behavior.
      seq = Halton(
          1, scramble=False, seed=_np.random.RandomState(2305982309)
      )
  
      x = cp.asarray(3 * seq.random(50))
      xitp = cp.asarray(3 * seq.random(50))
      y = _1d_test_function(x, cp)
  
      interp = cupyx.scipy.interpolate.RBFInterpolator(x, y)
  
      yitp1 = interp(xitp)
      yitp2 = pickle.loads(pickle.dumps(interp))(xitp)
  
      testing.assert_array_equal(yitp1, yitp2)
  
imports: import pickle
  import pytest
  import warnings
  import numpy
  from numpy.linalg import LinAlgError
  import cupy
  import cupyx
  from cupy import testing
  import cupyx.scipy.interpolate
  from cupyx.scipy.interpolate._rbfinterp import _AVAILABLE, _SCALE_INVARIANT, _NAME_TO_MIN_DEGREE, NAME_TO_FUNC, _monomial_powers, polynomial_matrix, kernel_matrix
label_desc: Use image node_id 22 for calling the _TestRBFInterpolator obj's underlying member method code with example usage: obj.test_pickleable() without return types