code: def test_stepsampler(plot=False):
      np.random.seed(6)
      region = make_region(len(paramnames))
      Ls = loglike_vectorized(region.u)
  
      stepsampler = CubeMHSampler(nsteps=len(paramnames))
      while True:
          u1, p1, L1, nc = stepsampler.__next__(
              region, -1e100, region.u, Ls, transform, loglike
          )
          if u1 is not None:
              break
      assert L1 > -1e100
      print(u1, L1)
      while True:
          u2, p2, L2, nc = stepsampler.__next__(
              region, -1e100, region.u, Ls, transform, loglike
          )
          if u2 is not None:
              break
      assert L2 > -1e100
      print(u2, L2)
      assert np.all(u1 != u2)
      assert np.all(L1 != L2)
  
imports: import numpy
  from ultranest.mlfriends import ScalingLayer, AffineLayer, MLFriends
  from ultranest import ReactiveNestedSampler
  from ultranest.stepsampler import RegionMHSampler, CubeMHSampler, CubeSliceSampler, RegionSliceSampler, SpeedVariableRegionSliceSampler, RegionBallSliceSampler
  from ultranest.stepsampler import generate_region_random_direction, ellipsoid_bracket, crop_bracket_at_unit_cube
  from ultranest.pathsampler import SamplingPathStepSampler
  from ultranest.stepsampler import select_random_livepoint, IslandPopulationRandomLivepointSelector
  from numpy.testing import assert_allclose
label_desc: Use image node_id 11 for calling a global function with example usage: test_stepsampler(plot) without return types