code: def get_prefix(sentence, prefix_len):
      """assuming no bpe, gets the prefix of the sentence with prefix_len words"""
      tokens = sentence.strip("\n").split()
      if prefix_len >= len(tokens):
          return sentence.strip("\n")
      else:
          return " ".join(tokens[:prefix_len])
  
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 5 for calling a global function with example usage: get_prefix(sentence, prefix_len) and returns: sentence, str