code: public static final BiMap<String, String> getCallSetNameMapping(Iterable<CallSet> callSets) {
      BiMap<String, String> idToName = HashBiMap.create();
      for(CallSet callSet : callSets) {
        // Dev Note: Be sure to keep this map loading as id -> name since it ensures that
        // the values are unique.
        idToName.put(callSet.getId(), callSet.getName());
      }
      return idToName.inverse();
    }
docs: Create a bi-directional map of names to ids for a collection of callsets.
  
  As a side effect, this will throw an IllegalArgumentException when the collection of callsets
  is malformed due to multiple is mapping to the same name.
  
  @param callSets
  @return the bi-directional map