code: def check_conf_percentage_validity(conf_percentage):
      
      msg = "conf_percentage MUST be a number between 0.0 and 100."
      condition_1 = isinstance(conf_percentage, Number)
      if not condition_1:
          raise ValueError(msg)
      else:
          condition_2 = 0 < conf_percentage < 100
          if not condition_2:
              raise ValueError(msg)
      return None
docs: Ensures that `conf_percentage` is in (0, 100). Raises a helpful ValueError
      if otherwise.