code: def test_degree_warning(self):
      y = np.linspace(0, 1, 5)[:, None]
      d = np.zeros(5)
      for kernel, deg in _NAME_TO_MIN_DEGREE.items():
          match = f"`degree` should not be below {deg}"
          with pytest.warns(Warning, match=match):
              self.build(
                  y, d, epsilon=1.0, kernel=kernel, degree=deg - 1
              )
  
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 19 for calling the _TestRBFInterpolator obj's underlying member method code with example usage: obj.test_degree_warning() without return types