class_docstr: Translation (Sequence Generation) task for Levenshtein Transformer
  See `"Levenshtein Transformer" <https://arxiv.org/abs/1905.11006>`_.
class_docstr_tok: ["Translation","(","Sequence","Generation",")","task","for","Levenshtein","Transformer","See","`","``","Levenshtein","Transformer","''","<","https",":","\/\/arxiv.org\/abs\/1905.11006",">","`","_","."]
code: def valid_step(self, sample, model, criterion):
      return self.trans_lev_task.valid_step(sample, model, criterion)
  
file_path: translate/pytorch_translate/tasks/translation_lev_task.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  from fairseq import options
  from fairseq.tasks import register_task
  from fairseq.tasks.translation_lev import TranslationLevenshteinTask
  from pytorch_translate.data import dictionary
  from pytorch_translate.tasks.pytorch_translate_task import PytorchTranslateTask
label_desc: Use image node_id 7 for calling the PytorchTranslationLevenshteinTask obj's underlying member method code with example usage: obj.valid_step(sample, model, criterion) and returns: self