code: def sentence_tokenizer(sentences):
      tokenized_sents = nltk.word_tokenize(sentences)
      return tokenized_sents
  
file_path: BigDL/python/dllib/src/bigdl/dllib/feature/dataset/sentence.py
imports: import nltk
  import os
  import itertools
  import sys
  from nltk.tokenize import word_tokenize
label_desc: Use image node_id 4 for calling a global function with example usage: sentence_tokenizer(sentences) and returns: tokenized_sents