code: def test_multiple_videos(self):
      with tempfile.NamedTemporaryFile(
          delete=False, suffix=".csv"
      ) as data_file:
          with temp_ava_dataset_2_videos() as (
              frame_paths_file,
              video_1,
              video_2,
              video_1_name,
              video_2_name,
          ):
              # add bounding boxes
              # video 1
              bb_1_a, bb_1_a_string = get_random_bbox()
              action_1_a, iou_1_a = 1, 0.85
              bb_1_b, bb_1_b_string = get_random_bbox()
              action_1_b, iou_1_b = 2, 0.4
  
              data_file.write(
                  (
                      f"{video_1_name},902,{bb_1_a_string},"
                      + f"{str(action_1_a)},{str(iou_1_a)}\n"
                  ).encode()
              )
              data_file.write(
                  (
                      f"{video_1_name},902,{bb_1_b_string},"
                      + f"{str(action_1_b)},{str(iou_1_b)}\n"
                  ).encode()
              )
              # video 2
              bb_2_a, bb_2_a_string = get_random_bbox()
              action_2_a, iou_2_a = 3, 0.95
              bb_2_b, bb_2_b_string = get_random_bbox()
              action_2_b, iou_2_b = 4, 0.9
  
              data_file.write(
                  (
                      f"{video_2_name},902,{bb_2_a_string},"
                      + f"{str(action_2_a)},{str(iou_2_a)}\n"
                  ).encode()
              )
              data_file.write(
                  (
                      f"{video_2_name},902,{bb_2_b_string},"
                      + f"{str(action_2_b)},{str(iou_2_b)}\n"
                  ).encode()
              )
  
              data_file.close()
  
              dataset = Ava(
                  frame_paths_file=frame_paths_file,
                  frame_labels_file=data_file.name,
                  clip_sampler=make_clip_sampler("random", 1.0),
              )
  
              # All videos are of the form cthw and fps is 30
              # Clip is samples at time step = 2 secs in video
              sample_1 = next(dataset)
              self.assertTrue(
                  sample_1["video"].equal(video_1[:, 45:75, :, :])
              )
              self.assertTrue(
                  torch.tensor(sample_1["boxes"]).equal(
                      torch.tensor([bb_1_a, bb_1_b])
                  )
              )
              self.assertTrue(
                  torch.tensor(sample_1["labels"]).equal(
                      torch.tensor([[action_1_a], [action_1_b]])
                  )
              )
              sample_2 = next(dataset)
              self.assertTrue(
                  sample_2["video"].equal(video_2[:, 45:75, :, :])
              )
              self.assertTrue(
                  torch.tensor(sample_2["boxes"]).equal(
                      torch.tensor([bb_2_a, bb_2_b])
                  )
              )
              self.assertTrue(
                  torch.tensor(sample_2["labels"]).equal(
                      torch.tensor([[action_2_a], [action_2_b]])
                  )
              )
  
file_path: pytorchvideo/tests/test_data_ava_dataset.py
imports: import contextlib
  import pathlib
  import random
  import tempfile
  import unittest
  import torch
  from pytorchvideo.data import Ava
  from pytorchvideo.data.clip_sampling import make_clip_sampler
  from utils import temp_frame_video
label_desc: Use image node_id 1 for calling the TestAvaDataset obj's underlying member method code with example usage: obj.test_multiple_videos() without return types