code: def generate_random_unique_indexes(count, nnz):
      """Utility to generate a list of random unique indexes in memory.
  
      Uses Knuth's n of k algorithm to generate the list in memory.
  
      :param count: The range of values to choose from.
      :type count: int
      :param nnz: The number of unique values to choose.
      :type nnz: int
      :return: The list of unique indexes of length nnz.
      :rtype: numpy.ndarray
      """
      if nnz > count:
          raise Exception("Knuth n-of-k algorithms requires 0 < n < k")
      indexes = np.zeros(nnz, dtype=int)
      current = 0
      i = 0
      while i < count and current < nnz:
          probability = (nnz - current) / (count - i)
          if random.random() < probability:
              indexes[current] = i
              current += 1
          i += 1
      return indexes
  
label_desc: Use image node_id 1 for calling a global function with example usage: generate_random_unique_indexes(count, nnz) and returns: indexes