code: def resolve_label_conflict(mapping, old_labels=None, new_labels=None):
      
  
      if old_labels is None:
          old_labels = set(mapping)
      if new_labels is None:
          new_labels = set(itervalues(mapping))
  
      # counter will be used to generate the intermediate labels, as an easy optimization
      # we start the counter with a high number because often variables are labeled by
      # integers starting from 0
      counter = itertools.count(2 * len(mapping))
  
      old_to_intermediate = {}
      intermediate_to_new = {}
  
      for old, new in iteritems(mapping):
          if old == new:
              # we can remove self-labels
              continue
  
          if old in new_labels or new in old_labels:
  
              # try to get a new unique label
              lbl = next(counter)
              while lbl in new_labels or lbl in old_labels:
                  lbl = next(counter)
  
              # add it to the mapping
              old_to_intermediate[old] = lbl
              intermediate_to_new[lbl] = new
  
          else:
              old_to_intermediate[old] = new
              # don't need to add it to intermediate_to_new because it is a self-label
  
      return old_to_intermediate, intermediate_to_new
docs: Resolve a self-labeling conflict by creating an intermediate labeling.
  
      Args:
          mapping (dict):
              A dict mapping the current variable labels to new ones.
  
          old_labels (set, optional, default=None):
              The keys of mapping. Can be passed in for performance reasons. These are not checked.
  
          new_labels (set, optional, default=None):
              The values of mapping. Can be passed in for performance reasons. These are not checked.
  
      Returns:
          tuple: A 2-tuple containing:
  
              dict: A map from the keys of mapping to an intermediate labeling
  
              dict: A map from the intermediate labeling to the values of mapping.