code: def _words_block_reader(self, stream):
      return sum(self._discourses_block_reader(stream)[0], [])
  
imports: import re
  from nltk.corpus.reader.api import *
  from nltk.corpus.reader.util import *
  from nltk.tag import map_tag, str2tuple
label_desc: Use image node_id 12 for calling the SwitchboardCorpusReader obj's underlying member method code with example usage: obj._words_block_reader(stream) and returns: sum