code: def concepts_to_str(concepts: List[Concept]) -> str:
      r"""
      Returns a string of hyphen("-") concatenated concept names.
      Example output: "striped-random_0-random_1"
  
      Args:
          concepts (list[Concept]): a List of concept names to be
                  concatenated and used as a concepts key. These concept
                  names are respective to the Concept objects used for
                  the classifier train.
      Returns:
          names_str (str): A string of hyphen("-") concatenated
                  concept names. Ex.: "striped-random_0-random_1"
      """
  
      return "-".join([str(c.id) for c in concepts])
  
label_desc: Use image node_id 1 for calling a global function with example usage: concepts_to_str(concepts) and returns: str