code: def _sanitize_string(unsanitized, itemsep, kvsep):
      
      sanitized = []
      kvs = unsanitized.split(itemsep)
      for kv in kvs:
          kv = kv.split(kvsep)
          if len(kv) == 2:
              sanitized.append((kv[0], _sanitize(kv[0], kv[1])))
          else:
              sanitized.append(kv)
      return itemsep.join(kvsep.join(kv) for kv in sanitized)
docs: sanitizes a string that contains multiple key/value items
      :param unsanitized: the unsanitized string
      :param itemsep: string that separates items
      :param kvsep: string that separates key from value
      :return: a sanitized string