code: def conll_tag_chunks(chunk_sents):
      """Convert each chunked sentence to list of (tag, chunk_tag) tuples,
      so the final result is a list of lists of (tag, chunk_tag) tuples.
      >>> from nltk.tree import Tree
      >>> t = Tree('S', [Tree('NP', [('the', 'DT'), ('book', 'NN')])])
      >>> conll_tag_chunks([t])
      [[('DT', 'B-NP'), ('NN', 'I-NP')]]
      """
      tagged_sents = [tree2conlltags(tree) for tree in chunk_sents]
      return [[(t, c) for (w, t, c) in sent] for sent in tagged_sents]
  
file_path: nltk-trainer/nltk_trainer/chunking/chunkers.py
imports: import nltk.tag
  from nltk.chunk import ChunkParserI
  from nltk.chunk.util import conlltags2tree, tree2conlltags
  from nltk.tag import UnigramTagger, BigramTagger, ClassifierBasedTagger
  from .transforms import node_label
label_desc: Use image node_id 2 for calling a global function with example usage: conll_tag_chunks(chunk_sents) and returns: unknown