code: def make_unique_name(name, existing_names, name_format="{name}_{index}", start=2):
      
      index = start
      new_name = name
      while new_name in existing_names:
          new_name = name_format.format(name=name, index=index)
          index += 1
  
      return new_name
docs: Return a unique name based on `name_format` and `name`.