./zipformer/export.py \
  --exp-dir zipformer/exp \
  --use-cr-ctc 1 \
  --use-ctc 1 \
  --use-transducer 0 \
  --use-attention-decoder 0 \
  --tokens data/lang_bpe_500/tokens.txt \
  --epoch 50 \
  --avg 24