code: def test_all_zeros(self):
      x = np.arange(10)
      y = np.zeros_like(x)
  
      # this should work and not generate any warnings
      with warnings.catch_warnings():
          warnings.filterwarnings("error")
          pch = pchip(x, y)
  
      xx = np.linspace(0, 9, 101)
      assert_equal(pch(xx), 0.0)
  
imports: import warnings
  import io
  import numpy
  from numpy.testing import assert_almost_equal, assert_array_equal, assert_array_almost_equal, assert_allclose, assert_equal, assert_
  from pytest import raises
  from scipy.interpolate import KroghInterpolator, krogh_interpolate, BarycentricInterpolator, barycentric_interpolate, approximate_taylor_polynomial, CubicHermiteSpline, pchip, PchipInterpolator, pchip_interpolate, Akima1DInterpolator, CubicSpline, make_interp_spline
label_desc: Use image node_id 7 for calling the TestPCHIP obj's underlying member method code with example usage: obj.test_all_zeros() without return types