code: def test_monotone_fn_inverter(self):
      x = [6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
      fn = lambda x: 1.0 / x  # noqa
      y = fn(np.array(x))
      f = monotone_fn_inverter(fn, x)
      npt.assert_array_equal(f.y, x[::-1])
      npt.assert_array_equal(f.x, y[::-1])
  
file_path: statsmodels/statsmodels/distributions/tests/test_ecdf.py
imports: import numpy
  import numpy.testing
  from numpy.testing import assert_raises
  from statsmodels.distributions import StepFunction, monotone_fn_inverter
  from statsmodels.distributions import ECDFDiscrete
label_desc: Use image node_id 5 for calling the TestDistributions obj's underlying member method code with example usage: obj.test_monotone_fn_inverter() without return types