class_docstr: Vectorized Gaussian Random Walk sampler.
docstr: Act upon region changed. Currently unused.
docstr_tok: ["Act","upon","region","changed",".","Currently","unused","."]
code: def region_changed(self, Ls, region):
      """Act upon region changed. Currently unused."""
      pass
  
imports: import numpy
  from ultranest.utils import submasks
  from ultranest.stepfuncs import evolve, step_back
  from ultranest.stepfuncs import generate_cube_oriented_direction, generate_cube_oriented_direction_scaled
  from ultranest.stepfuncs import generate_random_direction, generate_region_oriented_direction, generate_region_random_direction
  from ultranest.stepfuncs import generate_differential_direction, generate_mixture_random_direction
  import scipy.stats
label_desc: Use image node_id 3 for calling the PopulationRandomWalkSampler obj's underlying member method code with example usage: obj.region_changed(Ls, region) without return types