error: when using generate_lm.py for chinese

python3 generate_lm.py --input_txt TRANS.txt --output_dir . --top_k 500 --kenlm_bins /home/wieneralan/tmp/DeepSpeech/kenlm/build/bin/ --arpa_order 2 --max_arpa_memory "85%" --arpa_prune "0|0|1" --binary_a_bits 255 --binary_q_bits 8 --binary_type trie

error: Exception because `prune_thresholds.size() > order'.
You specified pruning thresholds for orders 1 through 3 but the model only has order 2

原因是：说了order是2，