docstr: Constructor of VQA helper class for reading and visualizing questions and answers.
  :param annotation_file (str): location of VQA annotation file
  :return:
docstr_tok: ["Constructor","of","VQA","helper","class","for","reading","and","visualizing","questions","and","answers",".",":","param","annotation_file","(","str",")",":","location","of","VQA","annotation","file",":","return",":"]
code: def __init__(self, annotation_file=None, question_file=None):
      """
      Constructor of VQA helper class for reading and visualizing questions and answers.
      :param annotation_file (str): location of VQA annotation file
      :return:
      """
      # load dataset
      self.dataset = {}
      self.questions = {}
      self.qa = {}
      self.qqa = {}
      self.imgToQA = {}
      if not annotation_file == None and not question_file == None:
          print("loading VQA annotations and questions into memory...")
          time_t = datetime.datetime.utcnow()
          dataset = json.load(open(annotation_file, "r"))
          questions = json.load(open(question_file, "r"))
          self.dataset = dataset
          self.questions = questions
          self.createIndex()
  
file_path: lavis/lavis/common/vqa_tools/vqa.py
imports: import json
  import datetime
  import copy
label_desc: Use image node_id 1 to create a new VQA object  with example: obj = VQA(annotation_file, question_file)