class_docstr: wapper of metric 
code: def __call__(self, *args, **kwargs):
      return self.call(*args, **kwargs)
  
imports: import os
  import abc
  from absl import logging
  import numpy
  from sklearn import metrics
  from seqeval.metrics import classification_report
  from delta.utils.register import registers
  from delta.utils.postprocess.postprocess_utils import ids_to_sentences
  from rouge import FilesRouge
  from sacrebleu import corpus_bleu
  from delta.utils.metrics import metric_utils
label_desc: Use image node_id 2 for calling the Metric obj's underlying member method code with example usage: obj.__call__() and returns: self