class_docstr: `AG News <https://arxiv.org/pdf/1509.01626.pdf>`_ is a News Topic classification dataset
  
  we use dataset provided by `LOTClass <https://github.com/yumeng5/LOTClass>`_
  
  Examples:
  
  ..  code-block:: python
  
      from openprompt.data_utils.text_classification_dataset import PROCESSORS
  
      base_path = "datasets/TextClassification"
  
      dataset_name = "agnews"
      dataset_path = os.path.join(base_path, dataset_name)
      processor = PROCESSORS[dataset_name.lower()]()
      trainvalid_dataset = processor.get_train_examples(dataset_path)
      test_dataset = processor.get_test_examples(dataset_path)
  
      assert processor.get_num_labels() == 4
      assert processor.get_labels() == ["World", "Sports", "Business", "Tech"]
      assert len(trainvalid_dataset) == 120000
      assert len(test_dataset) == 7600
      assert test_dataset[0].text_a == "Fears for T N pension after talks"
      assert test_dataset[0].text_b == "Unions representing workers at Turner   Newall say they are 'disappointed' after talks with stricken parent firm Federal Mogul."
      assert test_dataset[0].label == 2
code: def __init__(self):
      super().__init__()
      self.labels = ["World", "Sports", "Business", "Tech"]
  
imports: import os
  import json, csv
  from abc import ABC, abstractmethod
  from collections import defaultdict, Counter
  from typing import List, Dict, Callable
  from openprompt.utils.logging import logger
  from openprompt.data_utils.utils import InputExample
  from openprompt.data_utils.data_processor import DataProcessor
label_desc: Use image node_id 1 to create a new AgnewsProcessor object from inherited base classes: DataProcessor with example: obj = AgnewsProcessor()