code: def get_num_bpe_tokens_from_len(sentence, bpe_symbol, prefix_len):
      """given a prefix length in terms of words, return the number of bpe tokens"""
      prefix = get_prefix_no_bpe(sentence, bpe_symbol, prefix_len)
      assert len(remove_bpe(prefix, bpe_symbol).split()) <= prefix_len
      return len(prefix.split(" "))
  
imports: import math
  import os
  import re
  import subprocess
  from contextlib import redirect_stdout
  from fairseq import options
  from fairseq_cli import eval_lm, preprocess
label_desc: Use image node_id 8 for calling a global function with example usage: get_num_bpe_tokens_from_len(sentence, bpe_symbol, prefix_len) and returns: len