code: def _get_words(self, sentences):
      tags = [s.rows for s in sentences]
      tags = [t for sublist in tags for t in sublist]
      words = [t[0].lower() for t in tags]
      return words
  
imports: import math
  from underthesea.dictionary import Dictionary
  from collections import Counter, defaultdict
  from underthesea.utils import logger
  from datetime import date, timedelta
  import pandas
label_desc: Use image node_id 2 for calling the UDAnalyzer obj's underlying member method code with example usage: obj._get_words(sentences) and returns: words