code: def _add_merge(self, _from, _to):
      self.last_from = _from
      self.last_to = _to
      from_index = -1
      to_index = -1
  
      for index, region in enumerate(self.merge_regions):
          for r_index in region:
              if r_index == _from:
                  from_index = index
              if r_index == _to:
                  to_index = index
  
      if from_index != -1 and to_index != -1:
          if from_index != to_index:
              _tmp = copy.copy(self.merge_regions[from_index])
              _tmp.extend(self.merge_regions[to_index])
              self.merge_regions[from_index] = _tmp
              del self.merge_regions[to_index]
          return
  
      if from_index == -1 and to_index == -1:
          self.merge_regions.append([_from, _to])
          return
  
      if from_index != -1 and to_index == -1:
          self.merge_regions[from_index].append(_to)
          return
  
      if from_index == -1 and to_index != -1:
          self.merge_regions[to_index].append(_from)
          return
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import copy
  import math
  import time
  from io import IOBase
  from PIL import Image
  from skin_classifier import skin_classifier, Skin
label_desc: Use image node_id 5 for calling the Nude obj's underlying member method code with example usage: obj._add_merge(_from, _to) without return types