code: def chrf(items):
      """chrF++ is a tool for automatic evaluation of machine translation output
      based on character n-gram precision and recall enhanced with word n-grams.
      Source: https://github.com/m-popovic/chrF
      Paper: https://www.aclweb.org/anthology/W15-3049.pdf
  
      Higher is better  # TODO I think
      """
      refs = list(zip(*items))[0]
      preds = list(zip(*items))[1]
      refs, preds = _sacreformat(refs, preds)
      return sacrebleu.corpus_chrf(preds, refs).score
  
imports: import math
  from collections.abc import Iterable
  import numpy
  import sacrebleu
  import sklearn.metrics
  import random
  from collections import defaultdict
label_desc: Use image node_id 18 for calling a global function with example usage: chrf(items) and returns: sacrebleu