ChainParameters ret_hu_conv = new ChainParameters(null, ret);
ret_hu_conv.ptrs_to.add(ret_hu_conv);
ret_hu_conv.ptrs_to.add(best_block_arg);
ChainParameters ret_hu_conv = new ChainParameters(null, ret);
ret_hu_conv.ptrs_to.add(ret_hu_conv);
ret_hu_conv.ptrs_to.add(best_block_arg);