code: def test_can_specify_predictor(self):
      class Bidaf3Predictor(BidafPredictor):
          """same as bidaf predictor but with an extra field"""
  
          def predict_json(self, inputs):
              result = super(Bidaf3Predictor, self).predict_json(inputs)
              result["explicit"] = True
              return result
  
              Bidaf3Predictor = Predictor.register(
                  "bidaf-explicit"
              )  # pylint: disable=unused-variable(Bidaf3Predictor)
  
      with open(self.infile, "w") as f:
          f.write(
              """{"passage": "the seahawks won the super bowl in 2016", """
              """ "question": "when did the seahawks win the super bowl?"}\n"""
          )
          f.write(
              """{"passage": "the mariners won the super bowl in 2037", """
              """ "question": "when did the mariners win the super bowl?"}\n"""
          )
  
      sys.argv = [
          "run.py",  # executable
          "predict",  # command
          unicode(self.bidaf_model_path),
          unicode(self.infile),  # input_file
          "--output-file",
          unicode(self.outfile),
          "--predictor",
          "bidaf-explicit",
          "--silent",
      ]
  
      main()
      assert os.path.exists(self.outfile)
  
      with open(self.outfile, "r") as f:
          results = [json.loads(line) for line in f]
  
      assert len(results) == 2
      # Overridden predictor should output extra field
      for result in results:
          assert set(result.keys()) == set(
              [
                  "span_start_logits",
                  "span_end_logits",
                  "passage_question_attention",
                  "question_tokens",
                  "passage_tokens",
                  "span_start_probs",
                  "span_end_probs",
                  "best_span",
                  "best_span_str",
                  "explicit",
              ]
          )
  
      shutil.rmtree(self.tempdir)
  
imports: from __future__ import with_statement
  from __future__ import division
  from __future__ import absolute_import
  import argparse
  import csv
  import io
  import json
  import os
  import pathlib
  import shutil
  import sys
  import tempfile
  import pytest
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.util import JsonDict
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.commands import main
  from allennlp.commands.predict import Predict
  from allennlp.predictors import Predictor, BidafPredictor
  from io import open
label_desc: Use image node_id 7 for calling the TestPredict obj's underlying member method code with example usage: obj.test_can_specify_predictor() and returns: result