code: def add_string(self, ref, pred):
      self.ref.append(ref)
      self.pred.append(pred)
  
file_path: fairseq/fairseq/scoring/chrf.py
imports: from dataclasses import dataclass
  from fairseq.dataclass import FairseqDataclass
  from fairseq.scoring import BaseScorer, register_scorer
label_desc: Use image node_id 2 for calling the ChrFScorer obj's underlying member method code with example usage: obj.add_string(ref, pred) without return types