docs: public static int[] shape(INDArrayIndex... indices) {
          int[] ret = new int[indices.length];
          for (int i = 0; i < ret.length; i++) {
              // FIXME: LONG
              ret[i] = (int) indices[i].length();
          }
  
          List<Integer> nonZeros = new ArrayList<>();
          for (int i = 0; i < ret.length; i++) {
              if (ret[i] > 0)
                  nonZeros.add(ret[i]);
          }
  
          return ArrayUtil.toArray(nonZeros);
      }